@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 = {://000240380400006},
author = {Takahata, Y. and Okamoto, A. 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 = {://000221603000019},
author = {Takahata, Y. and Chong, D. P. and Segala, M.}
}
@article {750,
title = {DFT calculation of core-electron binding energies},
journal = {Journal of Electron Spectroscopy and Related Phenomena},
volume = {133},
number = {1-3},
year = {2003},
note = {ISI Document Delivery No.: 754ZWTimes Cited: 40Cited Reference Count: 70},
month = {Nov},
pages = {69-76},
type = {Article},
abstract = {A total of 59 core-electron binding energies (CEBEs) were studied with the Amsterdam Density Functional Program (ADF) program and compared with the observed values. The results indicate that a polarized triple-zeta basis set of Slater-type orbitals is adequate for routine assessment of the performance of each method of computation. With such a basis set, seven density functionals were tested. In addition, the performance of 21 energy density functionals were computed from the density calculated with the statistical average of orbital potentials (SAOP). Among all the choices tested, the best density functional for core-electron binding energies of C to F turns out to be the combination of Perdew-Wang (1986) functional for exchange and the Perdew-Wang (1991) functional for correlation, confirming earlier studies based on contracted Gaussian-type orbitals. For this best functional, five Slater-type orbital basis sets were examined, ranging from polarized double-zeta quality to the largest set available in the ADF package. For the best functional with the best basis set, the average absolute deviation (AAD) of the calculated value from experiment is only 0.16 eV (C) 2003 Elsevier B.V. All rights reserved.},
keywords = {ADF, BASIS-SETS, CEBE, CHEMICAL-SHIFTS, CONJUGATED, core-electron binding energy, CORRECT ASYMPTOTIC-BEHAVIOR, DENSITY-FUNCTIONAL CALCULATION, DFF, ESCA, EXCHANGE-ENERGY, GENERALIZED GRADIENT APPROXIMATION, MOLECULAR CALCULATIONS, MOLECULES, PHOTOELECTRON-SPECTROSCOPY, X-RAY-EMISSION, XPS},
isbn = {0368-2048},
url = {://000187364200010},
author = {Takahata, Y. and Chong, D. P.}
}