@article {ISI:000287150300002,
	title = {Electronic structure of S -nitrosothiols from sulfur K-edge X-ray absorption spectroscopy},
	journal = {Can. J. Chem.},
	volume = {89},
	number = {2},
	year = {2011},
	month = {feb},
	pages = {93{\textendash}97},
	abstract = {Sulfur K-edge X-ray absorption spectroscopy (S K-edge XAS) was applied to investigate the electronic structure of primary and tertiary S-nitrosothiols. Our experimental data, supported by density functional calculations, indicate that changes at C(alpha) affect the S-nitroso group through both inductive and direct orbital effects. Furthermore, our data are consistent with a weakening of the S-N bond in tertiary S-nitrosothiols as compared to their primary S-nitroso analogues. These results support existing computational models and suggest that the reactivity of S-nitrosothiols is not dominated by the electronics of the S-N bond.},
	keywords = {DFT, sulfur nitrosyls, XAS},
	issn = {0008-4042},
	doi = {10.1139/V10-083},
	url = {http://www.nrcresearchpress.com/doi/abs/10.1139/V10-083},
	author = {Martin-Diaconescu, Vlad and Perepichka, Inna and Bohle, D Scott and Kennepohl, Pierre}
}
@article {ISI:000273452200012,
	title = {Abnormal Reactivity of an N-Heterocyclic Carbene (NHC) with a Phosphaalkene: A Route to a 4-Phosphino-Substituted NHC},
	journal = {Angew. Chem. Int. Ed.},
	volume = {48},
	number = {52},
	year = {2009},
	pages = {9844{\textendash}9847},
	keywords = {carbenes, DFT},
	issn = {14337851},
	doi = {10.1002/anie.200905401},
	url = {http://www.ncbi.nlm.nih.gov/pubmed/19937891 http://doi.wiley.com/10.1002/anie.200905401},
	author = {Bates, Joshua I. and Kennepohl, Pierre and Gates, Derek P.}
}
@article {Martin-Diaconescu2009,
	title = {Effects of hyperconjugation on the electronic structure and photoreactivity of organic sulfonyl chlorides.},
	journal = {Inorg. Chem.},
	volume = {48},
	number = {3},
	year = {2009},
	month = {feb},
	pages = {1038{\textendash}44},
	publisher = {The University of British Columbia, Department of Chemistry, Vancouver, British Columbia V6T 1Z1.},
	abstract = {The electronic structure of organic sulfonyl compounds of the form RSO(2)G (G = -Cl, -OH, -CH(3)) is investigated to evaluate the effect of aryl R groups on photocleavage of the S-G bond. Sulfur K-edge X-ray absorption spectroscopy (XAS) provides a direct measure of the empty low-lying molecular orbitals in these complexes and, in combination with DFT calculations, a detailed description of the bonding in these compounds. The presence of an aryl group bound to the sulfonyl moiety has a significant impact on the spectroscopy and electronic structure of the site. The analysis suggests that the SCl(sigma*) orbital is significantly affected by mixing with the aryl pi* manifold. This mixing is dependent upon the nature of G and is most pronounced in the sulfonyl chlorides, where the energy of the SCl(sigma*) orbital is lowered by approximately 0.5 eV. The observed mixing is best described as excited-state hyperconjugation of the aryl pi system into the SCl(sigma*) orbital. The magnitude of the effect can be estimated directly from the S K-edge XAS spectra. These results are discussed in relation to the observed photochemistry of RSO(2)Cl, which is significantly enhanced when R = aryl as compared to alkyl substituents.},
	keywords = {DFT, ELECTRONS, models, MOLECULAR, molecular structure, Organic Chemicals, Organic Chemicals: chemistry, PHOTOCHEMISTRY, Spectrum Analysis, Sulfinic Acids, Sulfinic Acids: chemistry, sulfur redox, XAS},
	issn = {1520-510X},
	doi = {10.1021/ic801665f},
	url = {http://pubs.acs.org/doi/abs/10.1021/ic50073a047 http://www.ncbi.nlm.nih.gov/pubmed/19132932},
	author = {Martin-Diaconescu, Vlad and Kennepohl, Pierre}
}
@article {2591,
	title = {An evaluation of exchange-correlation functionals for the calculations of the ionization energies for atoms and molecules},
	journal = {Journal of Electron Spectroscopy and Related Phenomena},
	volume = {171},
	number = {1-3},
	year = {2009},
	note = {ISI Document Delivery No.: 452BQTimes Cited: 6Cited Reference Count: 82Segala, Maximiliano Chong, Delano P.},
	month = {Apr},
	pages = {18-23},
	type = {Article},
	abstract = {In this paper, ionization energies of gas-phase atoms and molecules are calculated by energy-difference method and by approximate transition-state models with density functional theory (DFT). To determine the best functionals for ionization energies, we first study the H to Ar atoms. An approximation is used in which the electron density is first obtained from Kohn-Sham computations with an exchange-correlation potential V-xc known as statistical average of orbital potentials (SAOP), after which the energy is computed from that density with 59 different exchange-correlation energy functionals E-xc. For the 18 atoms, the best E-xc functional providing an average absolute deviation (AAD) of only 0.110 eV is one known as the Krieger-Chen-lafrate-Savin functional modified by Krieger, Chen, Iafrate, and Kurth, if one uses the spin-polarized spherical atom description. On the other hand, if one imposes the condition of integer-electrons, the best functional is the Becke 1997 functional modified by Wilson, Bradley, and Tozer, with an AAD of 0.107 eV, while several other functionals perform almost as well. For molecules, we can achieve an accuracy of AAD = 0.21 eV for valence VIPs of nonperhalo molecules with Delta E(V-xc = SAOP;PBEO) using integer-electron description. For perhalo molecules our best approach is Delta E(V-xc from either E-xc or SAOP;mPW1PW) with full symmetry to obtain an AAD = 0.24 eV. (c) 2009 Elsevier B.V. All rights reserved.},
	keywords = {ADJUSTABLE-PARAMETERS, ASYMPTOTIC-BEHAVIOR, DFT, Energy-difference method, EXCITATION-ENERGIES, GENERALIZED GRADIENT APPROXIMATION, HE(II) PHOTOELECTRON-SPECTRA, Integer-electron, Ionization energy, models, ORBITAL MODEL POTENTIALS, ORGANIC-MOLECULES, PHOTO-ELECTRON SPECTRA, Slater-type orbitals, Spin-polarized spherical atom, STATISTICAL AVERAGE, TRANSITION-STATE},
	isbn = {0368-2048},
	url = {<Go to ISI>://000266515000002},
	author = {Segala, M. and Chong, D. P.}
}
@article {ISI:000270186500047,
	title = {Influence of oxygenation on the reactivity of ruthenium-thiolato bonds in arene anticancer complexes: insights from XAS and DFT.},
	journal = {J. Am. Chem. Soc.},
	volume = {131},
	number = {37},
	year = {2009},
	month = {sep},
	pages = {13355{\textendash}61},
	publisher = {American Chemical Society},
	abstract = {Thiolate ligand oxygenation is believed to activate cytotoxic half-sandwich [(eta(6)-arene)Ru(en)(SR)](+) complexes toward DNA binding. We have made detailed comparisons of the nature of the Ru-S bond in the parent thiolato complexes and mono- (sulfenato) and bis- (sulfinato) oxygenated species including the influence of substituents on the sulfur and arene. Sulfur K-edge XAS indicates that S(3p) donation into the Ru(4d) manifold depends strongly on the oxidation state of the sulfur atom, whereas Ru K-edge data suggest little change at the metal center. DFT results are in agreement with the experimental data and allow a more detailed analysis of the electronic contributions to the Ru-S bond. Overall, the total ligand charge donation to the metal center remains essentially unchanged upon ligand oxygenation, but the origin of the donation differs markedly. In sulfenato complexes, the terminal oxo group makes a large contribution to charge donation and even small electronic changes in the thiolato complexes are amplified upon ligand oxygenation, an observation which carries direct implications for the biological activity of this family of complexes. Details of Ru-S bonding in the mono-oxygenated complexes suggest that these should be most susceptible to ligand exchange, yet only if protonation of the terminal oxo group can occur. The potential consequences of these results for biological activation are discussed.},
	keywords = {Antineoplastic Agents, Antineoplastic Agents: chemical synthesis, Antineoplastic Agents: chemistry, Antineoplastic Agents: metabolism, AROMATIC, Aromatic: chemistry, DFT, DNA, DNA: metabolism, Drug Design, ELECTRONS, HYDROCARBONS, LIGANDS, metal-based drugs, models, MOLECULAR, Molecular Conformation, ORGANOMETALLIC COMPOUNDS, Organometallic Compounds: chemical synthesis, Organometallic Compounds: chemistry, Organometallic Compounds: metabolism, OXYGEN, Oxygen: chemistry, quantum theory, ruthenium, Ruthenium: chemistry, Spectrum Analysis, Sulfhydryl Compounds, Sulfhydryl Compounds: chemistry, X-Rays, XAS},
	issn = {1520-5126},
	doi = {10.1021/ja903405z},
	url = {http://www.ncbi.nlm.nih.gov/pubmed/19719101 http://dx.doi.org/10.1021/ja903405z},
	author = {Sriskandakumar, Thamayanthy and Petzold, Holm and Bruijnincx, Pieter C A and Habtemariam, Abraha and Sadler, Peter J and Kennepohl, Pierre}
}
@article {2392,
	title = {Theoretical study of the electronic spectra of s-triazine vapour},
	journal = {Canadian Journal of Chemistry-Revue Canadienne De Chimie},
	volume = {87},
	number = {8},
	year = {2009},
	note = {ISI Document Delivery No.: 493VQTimes Cited: 3Cited Reference Count: 37Chong, Delano P.},
	month = {Aug},
	pages = {1148-1153},
	type = {Article},
	abstract = {The ionization and excitation spectra of valence and core electrons of s-triazine in the gas phase are studied with ab initio, density functional, and semi-empirical methods. The results are compared with available experimental data and previous calculations. New estimates are proposed for the ionization energies of both valence and core electrons. The calculated excitation energies are consistent with experiment.},
	keywords = {AB-INITIO, AZINES, core-electron binding energies, DENSITY-FUNCTIONAL THEORY, DFT, electron spectra, ESCA, EXCHANGE-CORRELATION POTENTIALS, EXCITATION-ENERGIES, excitations, HYDROGEN, IONIZATION-POTENTIALS, ionizations, MOLECULAR CALCULATIONS, N-2, photoelectron spectra, s-triazine, SPECTROSCOPY, UV absorption},
	isbn = {0008-4042},
	url = {<Go to ISI>://000269766800008},
	author = {Chong, D. P.}
}
@article {2278,
	title = {Accurate calculation of N1s and C1s core electron binding energies of substituted pyridines. Correlation with basicity and with Hammett substituent constants},
	journal = {Journal of Molecular Structure-Theochem},
	volume = {863},
	number = {1-3},
	year = {2008},
	note = {ISI Document Delivery No.: 342NSTimes Cited: 6Cited Reference Count: 23Takahata, Yuji Wulfman, Carl E. Chong, Delano P.},
	month = {Aug},
	pages = {33-38},
	type = {Article},
	abstract = {Substituent shifts of the energetics of four related ionization processes of pyridines and benzoic acids (Fig. I) were investigated. The first process is core-electron ionization of gas-phase pyridines (Fig. 1A), while the second concerns gas-phase acid-base reaction between a substituted pyridine and a Conjugated acid (Fig. 1B), and the third and fourth processes are the acid dissociation of substituted benzoic acids in aqueous solution (Fig. 1C and in vacuum (Fig. 1D), respectively. Core-electron binding energies for the first process Were Calculated using density-functional theory with the scheme Delta E-KS (PW86x-PW91c/TZP+C-ret)//HF/6-31G*. Average absolute deviation of calculated core electron binding energy shifts at N atom in Substituted pyridines from experiment was 0.08 eV. The shift at N coincides highly with that at a ring carbon atom. The four shifts corresponding to the four processes shown in Figs. 1A-D correlate strongly with one another. with numerical values fairly close to each other when expressed in unit of electron volts. (C) 2008 Elsevier B.V. All rights reserved.},
	keywords = {acid dissociation, BENZENE-DERIVATIVES, CEBE shifts, DENSITY-FUNCTIONAL CALCULATION, DFT, Hammett substituent (sigma) constant, ionization processes, PARAMETERS, pyridines, SHIFTS, SIGMA CONSTANTS, SPECTROSCOPY},
	isbn = {0166-1280},
	url = {<Go to ISI>://000258791400006},
	author = {Takahata, Y. and Wulfman, C. E. and Chong, D. P.}
}
@article {ISI:000254858100027,
	title = {Assignment of Pre-edge Features in the Ru K-edge X-ray Absorption Spectra of Organometallic Ruthenium Complexes.},
	journal = {Inorg. Chim. Acta},
	volume = {361},
	number = {4},
	year = {2008},
	pages = {1059},
	abstract = {The nature of the lowest energy bound-state transition in the Ru K-edge X-ray Absorption Spectra for a series of Grubbs-type ruthenium complexes was investigated. The pre-edge feature was unambiguously assigned as resulting from formally electric dipole forbidden Ru 4d<{\textendash}1s transitions. The intensities of these transitions are extremely sensitive to the ligand environment and the symmetry of the metal centre. In centrosymmetric complexes the pre-edge is very weak since it is limited by the weak electric quadrupole intensity mechanism. By contrast, upon breaking centrosymmetry, Ru 5p-4d mixing allows for introduction of electric dipole allowed character resulting in a dramatic increase in the pre-edge intensity. The information content of this approach is explored as it relates to complexes of importance in olefin metathesis and its relevance as a tool for the study of reactive intermediates.},
	keywords = {DFT, OLEFIN METATHESIS, XAS},
	issn = {0020-1693},
	doi = {10.1016/j.ica.2007.07.029},
	url = {http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=2819416\&tool=pmcentrez\&rendertype=abstract},
	author = {Getty, Kendra and Delgado-Jaime, Mario Ulises and Kennepohl, Pierre}
}
@article {2046,
	title = {Density functional theory calculation of 2p spectra of SiH4, PH3, H2S, HCl, and Ar},
	journal = {International Journal of Quantum Chemistry},
	volume = {108},
	number = {8},
	year = {2008},
	note = {ISI Document Delivery No.: 297FSTimes Cited: 0Cited Reference Count: 48Chong, Delano P. Segala, Maximiliano Takahata, Yuji Baerends, E. J.},
	month = {Jul},
	pages = {1358-1368},
	type = {Article},
	abstract = {The method developed recently for prediction of Is electron spectra is now extended to the 2p spectra of SiH4, PH3, H2S, HCl, and Ar. The method for X-ray absorption spectra involves the use of Delta E for the excitation and ionization energies, and application of time-dependent density functional theory using the exchange-correlation potential known as statistical average of orbital potentials for the intensities. Additional assumptions and approximations are also made. The best exchange-correlation functional E-xc for the earlier calculation of Delta E in Is spectra of C to Ne (namely Perdew-Wang 1986 exchange, combined with Perdew-Wang 1991 correlation) is no longer used in this work on 2p spectra of Si to Ar. Instead, recently tested Exc good for 2p core-electron binding energies (known as OPTX) for exchange and LYP for correlation, plus scalar zeroth-order regular approximation is adopted here for the Delta E calculations. Our calculated X-ray absorption spectra are generally in good agreement with experiment. Although the predictions for the higher excitations suffer from basis set difficulties, our procedure should be helpful in the interpretation of absorption spectra of 2p electrons of Si to Ar. In addition, we report calculated results for other kinds of electron spectra for SiH4, PH3, H2S, HCl, and Ar, including valence electron ionizations and excitations as well as X-ray emission. (C) 2008 Wiley Periodicals, Inc.},
	keywords = {2p spectra, ACCURATE, CORE, DFT, ELECTRON BINDING-ENERGIES, EXCHANGE-CORRELATION POTENTIALS, EXCITATION-ENERGIES, excitations, EXCITED-STATES, GAS, INNER, ionizations, MOLECULES, PHOTOELECTRON-SPECTRA, X-ray absorption spectra, X-ray emission spectra},
	isbn = {0020-7608},
	url = {<Go to ISI>://000255603100007},
	author = {Chong, D. P. and Segala, M. and Takahata, Y. and Baerends, E. J.}
}
@article {ISI:000254173600010,
	title = {N-heterocyclic carbene complexes of Rh: reaction with dioxygen without oxidation.},
	journal = {J. Am. Chem. Soc.},
	volume = {130},
	number = {12},
	year = {2008},
	month = {mar},
	pages = {3724{\textendash}5},
	abstract = {The reaction of oxygen with rhodium complexes containing N-heterocyclic carbenes was found to give dioxygen complexes with rare square planar geometries and unusually short O-O bond lengths. Analysis of the bonding in these complexes by Rh L-edge X-ray absorption spectroscopy (XAS), Raman spectroscopy, and DFT calculations provides evidence for a bonding model in which singlet oxygen is bound to a Rh(I) d8 metal complex, rather than the more common Rh(III) d6 peroxo species with octahedral geometry and O-O bond lengths in the 1.4-1.5 A range.},
	keywords = {chemical, DFT, dioxygen complexes, Heterocyclic Compounds, Heterocyclic Compounds: chemistry, METHANE, Methane: analogs \& derivatives, Methane: chemistry, models, MOLECULAR, molecular structure, ORGANOMETALLIC COMPOUNDS, Organometallic Compounds: chemical synthesis, Organometallic Compounds: chemistry, OXYGEN, Oxygen: chemistry, rhodium, Rhodium: chemistry, SPECTROMETRY, X-Ray Emission, X-Ray Emission: methods, XAS},
	issn = {1520-5126},
	doi = {10.1021/ja7108213},
	url = {http://www.ncbi.nlm.nih.gov/pubmed/18321109},
	author = {Praetorius, Jeremy M and Allen, Daryl P and Wang, Ruiyao and Webb, Jonathan D and Grein, Friedrich and Kennepohl, Pierre and Crudden, Cathleen M}
}
@article {ISI:000251974000023,
	title = {An electronic rationale for observed initiation rates in ruthenium-mediated olefin metathesis: charge donation in phosphine and N-heterocyclic carbene ligands.},
	journal = {J. Am. Chem. Soc.},
	volume = {129},
	number = {51},
	year = {2007},
	month = {dec},
	pages = {15774{\textendash}6},
	chapter = {15774},
	abstract = {Ru K-edge XAS data indicate that second generation ruthenium-based olefin metathesis precatalysts (L = N-heterocyclic carbene) possess a more electron-deficient metal center than in the corresponding first generation species (L = tricyclohexylphosphine). This surprising effect is also observed from DFT calculations and provides a simple rationale for the slow phosphine dissociation kinetics previously noted for second-generation metathesis precatalysts.},
	keywords = {ALKENES, Alkenes: chemistry, BOND, carbenes, CATALYSTS, CL, DFT, ELECTRONS, Heterocyclic Compounds, Heterocyclic Compounds: chemistry, HYDROCARBONS, Hydrocarbons: chemistry, KINETICS, LIGANDS, MECHANISM, METHANE, Methane: analogs \& derivatives, Methane: chemistry, MOIETY, NHC LIGANDS, OLEFIN METATHESIS, phosphines, Phosphines: chemistry, RAY-ABSORPTION SPECTROSCOPY, ruthenium, Ruthenium: chemistry, TRANSITION-METAL-COMPLEXES, XAS},
	isbn = {0002-7863},
	issn = {1520-5126},
	doi = {10.1021/ja0747674},
	url = {<Go to ISI>://000251974000023 http://www.ncbi.nlm.nih.gov/pubmed/18047332},
	author = {Getty, Kendra and Delgado-Jaime, Mario Ulises and Kennepohl, Pierre}
}
@article {ISI:000244896900002,
	title = {Sulfur K-edge XAS as a probe of sulfur-centered radical intermediates.},
	journal = {J. Am. Chem. Soc.},
	volume = {129},
	number = {11},
	year = {2007},
	month = {mar},
	pages = {3034{\textendash}5},
	abstract = {Sulfur K-edge XAS is used in the identification and characterization of sulfur based radicals obtained from UV irradiated glutathione. Ground state and time-dependent DFT calculations are used to identify thiyl (RS center dot) and perthiyl (RSS center dot) radical species.},
	keywords = {DFT, Free Radicals, Free Radicals: analysis, Free Radicals: chemistry, GLUTATHIONE, Glutathione: chemistry, Oxidation-Reduction, PHOTOCHEMISTRY, SPECTROMETRY, SPECTROPHOTOMETRY, Sulfhydryl Compounds, Sulfhydryl Compounds: chemistry, SULFUR, sulfur redox, Sulfur: chemistry, ULTRAVIOLET, X-Ray Emission, X-Ray Emission: methods, XAS},
	issn = {0002-7863},
	doi = {10.1021/ja0676760},
	url = {http://www.ncbi.nlm.nih.gov/pubmed/17319664},
	author = {Martin-Diaconescu, Vlad and Kennepohl, Pierre}
}
@article {1585,
	title = {DFT calculation of core-electron binding energies of pyrimidine and purine bases},
	journal = {International Journal of Quantum Chemistry},
	volume = {106},
	number = {13},
	year = {2006},
	note = {ISI Document Delivery No.: 082IQTimes Cited: 12Cited Reference Count: 12Takahata, Yuji Okamoto, Andre K. Chong, Delano P.13th Brazilian Symposium of Theoretical ChemistryNOV 20-23, 2005Sao Pedro, BRAZILNatl Res Council, CAPES, Rede Nanotecnol Mole \& Interfaces, FAPESP, FAPERJ, FAPDFSp. Iss. SI},
	month = {Nov},
	pages = {2581-2586},
	type = {Proceedings Paper},
	abstract = {We calculated the accurate core-electron binding energies (CEBEs) of pyrimidine and purine bases in their isolated forms in the gas phase, i.e., uracil (U), thymine (T), cytosine (C), adenine (A), and guanine (G), using density functional theory (DFT) with the scheme Delta E (PW86-PW91)/TZP//HF/6-31G*. The relative magnitude of calculated CEBEs of the same type of atom in the gas phase pyrimidine and purine bases reflect its chemical environment. Comparison between the calculated CEBEs of the bases in the gas phase and observed CEBEs of the same molecules in the solid state permitted estimation of the approximate work functions (WD). Using the approximate WD, it was possible to calculate approximate CEBEs of the DNA bases in the solid state. The average absolute deviation from experiment was 0.37 eV. (C) 2006 Wiley Periodicals, Inc.},
	keywords = {ACCURATE, CEBE, DFT, DNA bases, ESCA, SHIFTS},
	isbn = {0020-7608},
	url = {<Go to ISI>://000240380400006},
	author = {Takahata, Y. and Okamoto, A. K. and Chong, D. P.}
}
@article {1082,
	title = {Density functional calculation of K-shell spectra of small molecules},
	journal = {Journal of Electron Spectroscopy and Related Phenomena},
	volume = {148},
	number = {2},
	year = {2005},
	note = {ISI Document Delivery No.: 945UITimes Cited: 10Cited Reference Count: 44},
	month = {Aug},
	pages = {115-121},
	type = {Article},
	abstract = {Both Delta E-KS and time-dependent density functional theory (TD-DFT) methods, with approximations for the singlet-triplet splitting and for the relativistic corrections, were tested for the calculation of K-shell spectra of Ne, HF, H2O, NH3, CH4, and CO. Results from several exchange-correlation functionals as well as diffuse basis sets were compared with available experimental data. Excellent core excitation and core-electron ionization energies for Ne, HF, H2O, NH3, CH4, and CO can be obtained from Delta E with Perdew-Wang 1986 exchange and Perdew-Wang 1991 correlation functionals; and reasonable intensities for singlet excitations, from TD-DFT with exchange-correlation potential known as statistical average of orbital potentials. The dependence of the quality of Delta E on basis set is as expected: excitations to higher Rydberg levels requiring more diffuse functions. However, the oscillator strength seems to be more sensitive to the quality of the basis set. Suggestions are made for extending the procedure to larger systems. (c) 2005 Elsevier B.V. All rights reserved.},
	keywords = {ACCURATE, CO, core-electron binding energies, DFT, diffuse STO functions, EDGE, ELECTRON BINDING-ENERGIES, EXCITATION, EXCITED-STATES, GAS-PHASE, inner-shell excitation spectra, intensities, NEON, OSCILLATOR-STRENGTHS, relative, Rydberg levels, Slater-type orbitals, SPECTROSCOPY, time-dependent DFT},
	isbn = {0368-2048},
	url = {<Go to ISI>://000230527300007},
	author = {Chong, D. P.}
}
@article {1278,
	title = {Estimation of Hammett sigma constants of substituted benzenes through accurate density-functional calculation of core-electron binding energy shifts},
	journal = {International Journal of Quantum Chemistry},
	volume = {103},
	number = {5},
	year = {2005},
	note = {ISI Document Delivery No.: 929WJTimes Cited: 16Cited Reference Count: 1212th Brazilian Symposium of Theoretical ChemistryNOV 23-26, 2003Caxambu, BRAZIL},
	month = {Jun},
	pages = {509-515},
	type = {Proceedings Paper},
	abstract = {For substituted benzenes such as (p-F-C6H4-Z), Linderberg et al. [1] demonstrated the validity of an equation similar to: Delta CEBE approximate to K sigma, where Delta CEBE is the difference in core-electron binding energies (CEBEs) of the fluorinated carbon in p-F-C,H,-Z and that in FC6H5, the parameter K a function of the type of reaction, and sigma is the Hammett substituent (sigma) constant. In this work, CEBEs of ring carbon atoms for a series of para disubstituted molecules p-F-C,H,-Z were first calculated using Density Functional Theory (DFT) with the scheme Delta E-ks (PW86-PW91)/TZP+C-rel//HF/6-31G*. An average absolute deviation of 0.13 eV from experiment was obtained for the CEBEs. Then we performed a linear regression analysis in the form of Y = A+B*X for a plot of Hammett up constants against calculated shifts Delta CEBEs (in eV) for the fluorinated carbon. The results were: A = -0.08 and B = 1.01, with correlation coefficient R = 0.973, standard deviation = 0.12, and P < 0.0001. The intercept A of the fitted line, close to zero, shows that the Hammett sigma(p) constant is proportional to the calculated Delta CEBES. On the other hand, the slope B of the straight line gives an estimate of the parameter K. Similar statistical correlations were obtained for the carbon atoms ortho and meta to the substituent Z. (c) 2005 Wiley Periodicals, Inc.},
	keywords = {DCEBE, DERIVATIVES, DFT, disubstitued benzenes FC(6)H(4)Z, Hammett sigma-constant},
	isbn = {0020-7608},
	url = {<Go to ISI>://000229377000005},
	author = {Takahata, Y. and Chong, D. P.}
}
@article {949,
	title = {Electron binding energies of Si 2p and S 2p for Si- and S-containing substances by DFT calculations using the model molecules},
	journal = {Polymer Journal},
	volume = {36},
	number = {8},
	year = {2004},
	note = {ISI Document Delivery No.: 860UCTimes Cited: 2Cited Reference Count: 39},
	pages = {600-606},
	type = {Article},
	abstract = {Si 2p and S 2p core-electron binding energies (CEBE)s of Si- and S-containing molecules were calculated by deMon DFT program using Slater{\textquoteright}s transition-state (TS) concept. In the previous works, we could not obtain the calculated values to the experimental ones of third periodic 2p CEBEs for the molecules within the range of averaged absolute deviation (AAD) of 1.0eV, although the values were calculated by the unrestricted generalized transition-state (uGTS) method. Here, we were able to get the reasonable Si 2p and S 2p CEBEs of 11, and 12 gas molecules in the AAD of 0.37 and 0.46 eV, respectively from the CEBE calculations by the unrestricted generalized diffuse ionization (uGDI) method with a modification of screening constants for third periodic elements of the 2p core-hole. Furthermore, we estimated WD (work function and the other energies) values of seven Si- and S-containing polymers [(Si(CH3)(2))(n) (PDMS), (Si(CH3)(2)O)(n), (PDMSO), (Si(C6H5)CH3)(n) (PMPS), (Si(C6H5)CH3O)(n) (PPMSO), ((CH2CH2)S)(n) (PETHS), ((CH2(CH2)(4)CH2)SO2). (PHMS), ((C6H4)S)(n) (PPS)] from the differences between calculated CEBE values for the model molecules and experimental ones on the solid polymers.},
	keywords = {APPROXIMATION, CALCULATIONS, CORE, core-electron binding energy, DENSITY-FUNCTIONAL THEORY, DFT, EMISSION-SPECTRA, ESCA, FILMS, FLUORESCENCE, ION IRRADIATION, POLYMER CONVERSION, X-ray photoelectron, X-ray photoelectron spectra},
	isbn = {0032-3896},
	url = {<Go to ISI>://000224367800004},
	author = {Motozaki, W. and Otsuka, T. and Endo, K. and Chong, D. P.}
}
@article {1002,
	title = {Is HAM/3 (Hydrogenic Atoms in Molecules, Version 3) a semiempirical version of DFT (density functional theory) for ionization processes?},
	journal = {Journal of the Brazilian Chemical Society},
	volume = {15},
	number = {2},
	year = {2004},
	note = {ISI Document Delivery No.: 823IBTimes Cited: 7Cited Reference Count: 69},
	month = {Mar-Apr},
	pages = {282-291},
	type = {Article},
	abstract = {We calculated valence-electron vertical ionization potentials (VIPs) of nine small molecules, plus uracil and C2F4, by several different methods: semiempirical HAM/3 and AM1 methods, different nonempirical DFT models such as uDI(B88-P86)/cc-pVTZ and -epsilon(SAOP)/TZP, and ab initio Hartree-Fock (HF)/cc-pVTZ. HAM/3 reproduced numerical values more closely to those calculated by the nonempirical DFTs than to those obtained by HF method. Core-electron binding energies (CEBEs) of aniline, nitrobenzene and p-nitro aniline, were also calculated by HAM/3 and nonempirical DeltaFT using DE method. A nonempirical DFT model, designated as DeltaE(KS) (PW86-PW91)/TZP model, resulted accurate CEBEs ( average absolute deviation of 0.14 eV) with high efficiency. Although absolute magnitude of HAM/3 CEBEs has error as much as 3 eV, the error in the chemical shifts DeltaCEBE is much smaller at 0.55 eV. While the CEBE results do not lead to any definite answer to the question in the title, the trends in valence-electron VIPs indicate that HAM/3 does not approximate DFT with accurate exchange-correlation potentials, but seems to simulate approximate functionals such as B88-P86.},
	keywords = {ACCURATE, BASIS-SET, CEBE, DFT, ELECTRON BINDING-ENERGIES, ESCA, EXCHANGE-ENERGY, HAM-3, HAM/3, MO THEORY, ORGANIC-MOLECULES, RAY PHOTOELECTRON-SPECTROSCOPY, SPECTRA, SUBSTITUTED BENZENES, vertical ionization potential, ZETA},
	isbn = {0103-5053},
	url = {<Go to ISI>://000221603000019},
	author = {Takahata, Y. and Chong, D. P. and Segala, M.}
}
@article {5195,
	title = {PW86-PW91 density functional calculation of vertical ionization potentials: Some implications for present-day functionals},
	journal = {International Journal of Quantum Chemistry},
	volume = {81},
	number = {1},
	year = {2001},
	note = {ISI Document Delivery No.: 380EFTimes Cited: 14Cited Reference Count: 50},
	month = {Jan},
	pages = {34-52},
	type = {Article},
	abstract = {A total of 181 vertical ionization potentials (VIPs) of 41 molecules were calculated by density functional theory (DFT) employing the Perdew-Wang 1986 (PW86) exchange and Perdew-Wang 1991 (PW91) correlation functionals and using the aug-cc-pV5Z basis and experimental ground-state geometries. The overall average absolute deviation (AAD) from experiment was found to be 0.55 eV and only 0.31 eV for linear molecules but 0.86 eV for nonplanar molecules. A number of VIPs were in error by over 2 eV. In particular, DFT performed most poorly when ionization was from an orbital with highly varying density gradients (which arise from the orbital{\textquoteright}s shape or compactness or through its density being distributed over a number of atoms). Indications are that many or all present-day functionals suffer from the same failings. (C) 2001 John Wiley \& Sons, Inc.},
	keywords = {ACCURATE, AROMATIC MOLECULES, CORRELATED MOLECULAR CALCULATIONS, DFT, EXCHANGE-ENERGY, functionals, GAUSSIAN-BASIS SETS, HE(II) PHOTOELECTRON-SPECTRA, ionization potential, ORGANIC-MOLECULES, PHOTO-ELECTRON SPECTRA, PW86, PW91, SPECTROSCOPY, WAVE-FUNCTIONS},
	isbn = {0020-7608},
	url = {<Go to ISI>://000165685400007},
	author = {Shapley, W. A. and Chong, D. P.}
}
@article {4768,
	title = {Accurate density-functional calculation of core-electron binding energies with a scaled polarized triple-zeta basis set - VII. Effects of poorer geometry and poorer basis sets},
	journal = {Journal of Electron Spectroscopy and Related Phenomena},
	volume = {106},
	number = {1},
	year = {2000},
	note = {ISI Document Delivery No.: 274BPTimes Cited: 7Cited Reference Count: 40},
	month = {Jan},
	pages = {1-6},
	type = {Article},
	abstract = {Our efficient method of calculating accurate core-electron binding energies has been applied to many cases. In order to extend the application to larger systems, such as oligomers and clusters; model polymers; and adsorbates on metals, respectively, the use slightly smaller basis sets and geometry optimized by a semiempirical molecular orbital method such as Austin Model I, without sacrificing accuracy should be aimed for. In this paper, we report the results of our study on the effects of using such poorer geometry and poorer basis sets. (C) 2000 Elsevier Science B.V. All rights reserved.},
	keywords = {AFFINITIES, APPROXIMATION, ATOMS, core-electron binding energies, DFT, ESCA, ethyl perfluoroacetate, GAS-PHASE, ISOMERS, MOLECULES, SPECTRA, XPS},
	isbn = {0368-2048},
	url = {<Go to ISI>://000084744100001},
	author = {Chong, D. P. and Bureau, C.}
}
@article {4769,
	title = {Density functional calculation of core-electron binding energies of isomers of C3H6O2 and C3H5NO},
	journal = {International Journal of Quantum Chemistry},
	volume = {76},
	number = {1},
	year = {2000},
	note = {ISI Document Delivery No.: 262BNTimes Cited: 4Cited Reference Count: 25},
	month = {Jan},
	pages = {44-50},
	type = {Article},
	abstract = {The core-electron binding energies of six isomers of C3H6O2 and four isomers of C3H5NO were calculated by a DFT/uGTS/scaled-pVTZ approach. An average absolute deviation from experiment of 0.15 eV was found for 14 C, N, and O Is energies. The results confirm the distinctive nature of the X-ray photoelectron spectra (XPS) of isomers and support the use of electron spectroscopy complemented by accurate theoretical predictions as a tool for chemical analysis. (C) 2000 John Wiley \& Sons, Inc.},
	keywords = {APPROXIMATION, ATOMS, core-electron binding energies, DFT, ISOMERS, MOLECULES, ZETA BASIS-SET},
	isbn = {0020-7608},
	url = {<Go to ISI>://000084046000004},
	author = {Chong, D. P. and Cavigliasso, G.}
}
@article {4502,
	title = {Accurate density-functional calculation of core-electron binding energies with a scaled polarized triple-zeta basis set. VI: Extension to boron-containing molecules},
	journal = {Canadian Journal of Chemistry-Revue Canadienne De Chimie},
	volume = {77},
	number = {1},
	year = {1999},
	note = {ISI Document Delivery No.: 185AQTimes Cited: 10Cited Reference Count: 25},
	month = {Jan},
	pages = {24-27},
	type = {Article},
	abstract = {Our procedure for calculating core-electron binding energies (CEBEs), based on the unrestricted generalized transition state model using B88/P86 functional, was extended to boron-containing molecules. Both unsealed (cc-pVTZ, cc-pVQZ, cc-pV5Z) and scaled (scaled-pVTZ and scaled-pVQZ) basis sets were used. The average absolute deviation from experiment for boron CEBEs with the scaled-pVTZ basis set was found to be 0.24 eV, compared to 0.23 eV for the much larger cc-pV5Z basis set.},
	keywords = {APPROXIMATION, ATOMS, BORON, core-electron binding energies, DFT, GAUSSIAN-BASIS SETS, ISOMERS},
	isbn = {0008-4042},
	url = {<Go to ISI>://000079646300004},
	author = {Cavigliasso, G. and Chong, D. P.}
}
