@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 {4947, title = {Theoretical valence photoelectron and UV-visible absorption spectra of four stable conductive molecules obtained by MO calculations}, journal = {Bulletin of the Chemical Society of Japan}, volume = {73}, number = {1}, year = {2000}, note = {ISI Document Delivery No.: 284WKTimes Cited: 4Cited Reference Count: 31}, month = {Jan}, pages = {43-51}, type = {Article}, abstract = {Theoretical valence photoelectron and UV-visible absorption spectra of four stable conductive molecules (N, N{\textquoteright}-diphenyl-1,4-phenylenediamine (DPPD), p-quaterphenyl (PQP), 2, 3, 7, 8, 12, 13, 17, 18-octaethyl-21H, 23H-porphyrin (OEP), and 29H, 31H-phthalocyanine (PC)) have been obtained by semiempirical HAM/3 and ZINDO MO calculations, respectively. The Al K alpha photoelectron spectra were simulated using Gaussian lineshape functions of an approximate linewidth 0.10 E-k (E-k = E-k{\textquoteright} - WD), where E-k{\textquoteright} is the vertical ionization potential (VIP) of each MO and WD is a shift to account for sample work function and other energy effects, as stated in previous studies. The theoretical valence spectra of the four conductive compounds are in good accordance with the observed ones. The theoretical UV-visible absorption curves of DPPD, PQP, OEP, and PC were obtained after AM1 calculations with COSMO option to reflect solvent effects. The absorption curves as simulated with Gaussian lineshape functions of a constant linewidth of 0.003 eV. Correspond well to the observed spectra. For PC, the simulated spectrum which consists of 0.5 inner protonation (IP) and 0.5 outer protonation (OP) types for PC-ring shows much better agreement with the experimental spectrum in H2SO4 than the spectrum of either TP or OP type alone.}, keywords = {HAM-3, MODEL, OLIGOMERS, PHTHALOCYANINES, POLYMERS, STATES, XPS}, isbn = {0009-2673}, url = {://000085355700005}, author = {Takaoka, K. and Maeda, S. and Miura, H. and Otsuka, T. and Endo, K. and Chong, D. P.} } @article {4415, title = {Theoretical valence XPS and UV-visible absorption spectra of four leucodyes using MO calculations}, journal = {Bulletin of the Chemical Society of Japan}, volume = {71}, number = {4}, year = {1998}, note = {ISI Document Delivery No.: ZP865Times Cited: 8Cited Reference Count: 26}, month = {Apr}, pages = {807-816}, type = {Article}, abstract = {Semiempirical HAM/3 MO program was used to obtain the theoretical valence X-ray photoelectron spectra (XPS) of the two leuco dyes (2{\textquoteright}-anilino-6{\textquoteright}-diethylamino-3{\textquoteright}-methylspiro[isobenzofuran-1(3H),9{\textquoteright}-[9H] xanthene]-3-one (DEAMAF) and 3,3-bis(4-dimethylaminophenyl)-6-dimethylamino-1(3H)-isobenzofuranone (CVL)) and UV-visible adsorption spectra of the four leuco dyes (DEAMAF, CVL, 2{\textquoteright}-chloro-6{\textquoteright}-diethylamino-3{\textquoteright}-methylspiro[isobenzofuran-1 (3H),9{\textquoteright}-[9H]xanthene]3-one (DEAMCF), and 3{\textquoteright},6{\textquoteright}-bis(diethylamino)-spiro [isobenzofuran-1 (3H),9{\textquoteright}-[9H]]xanthene]-3-one (Rhodamine B base). The calculated Al K alpha photoelectron spectra were obtained using Gaussian lineshape functions of an approximate linewidth 0.10E(k) (E-k = E{\textquoteright}(k) -WD), where E{\textquoteright}(k) is the vertical ionization potential (VIP) of each MO and WD is a shift to account for sample work function, polarization energy and other energy effects. On the other hand, the absorption curves were simulated with Gaussian lineshape functions of a constant linewidth of 0.02 eV. The theoretical valence energy levels corresponded well to the spectra of two leuco dyes observed 0-40 eV, while the simulated adsorption spectra were shifted for a good fit with the experimental solution spectra in the range of 250-700 nm.}, keywords = {HAM-3, MODEL, POLYMERS, RAY PHOTOELECTRON-SPECTRA}, isbn = {0009-2673}, url = {://000073796400006}, author = {Takaoka, K. and Maeda, S. and Miura, H. and Endo, K. and Chong, D. P.} } @article {3631, title = {Density functional calculation of core-electron binding energies of glycine conformers}, journal = {Canadian Journal of Chemistry-Revue Canadienne De Chimie}, volume = {74}, number = {6}, year = {1996}, note = {ISI Document Delivery No.: VA966Times Cited: 19Cited Reference Count: 23}, month = {Jun}, pages = {1005-1007}, type = {Article}, abstract = {Our recent procedure of computing accurate core-electron binding energies (CEBEs) with density-functional theory is applied to glycine conformers in this work. The procedure uses the unrestricted generalized transition-state model and a combined functional of Becke{\textquoteright}s 1988 exchange with Perdew{\textquoteright}s 1986 correlation. When a large basis set such as Dunning{\textquoteright}s correlation-consistent polarized valence quadruple zeta set is used, the average absolute deviation from experiment for the CEBEs of the most stable conformer of glycine is only 0.2 eV, compared with 18 eV for Koopmans{\textquoteright} theorem.}, keywords = {APPROXIMATION, BASIS-SETS, core-electron binding energies, DENSITY-FUNCTIONAL THEORY, GAS, GLYCINE, HAM-3, SEMIEMPIRICAL MO THEORY}, isbn = {0008-4042}, url = {://A1996VA96600029}, author = {Chong, D. P.} } @article {3312, title = {SIMULATION OF THE VALENCE X-RAY PHOTOELECTRON-SPECTRA OF 16 POLYMERS BY THE SEMIEMPIRICAL HAM/3 MO METHOD USING THE MODEL MOLECULES}, journal = {Bulletin of the Chemical Society of Japan}, volume = {68}, number = {2}, year = {1995}, note = {ISI Document Delivery No.: QP061Times Cited: 17Cited Reference Count: 40}, month = {Feb}, pages = {528-538}, type = {Article}, abstract = {The HAM/3 method was used to provide a better assignment of the valence X-ray photoelectron spectra of 16 polymers involving nitrogen, oxygen, fluorine, a glucose unit, and a benzene nucleus using the monomer, dimer or trimer model molecules without consideration of the contraction factor of the energy scale. The calculated A1 K alpha photoelectron spectra were obtained using Gaussian functions of a fixed approximate linewidth, 0.10 I-k and I-k=I-k{\textquoteright}-WD, where I-K{\textquoteright} is the vertical ionization potential of each MO and WD is an approximate shift to account for the work function of the sample and other energy (polarization energy and so on) effects. We assumed that WD corresponds to the shift that we must apply before we can compare the calculated spectrum for the single model molecule with the observed spectrum for the solid. The approximate linewidth corresponds to the experimental result that the inner valence spectra are broader. The theoretical spectra showed good agreement with the spectra of the polymers observed between 0-40 eV.}, keywords = {CO2, CORE, ELECTRONIC-STRUCTURE, ENERGY-LEVELS, ESCA, HAM-3, N2O, POLYOXYMETHYLENE, SPECTROSCOPY, XPS SPECTRA}, isbn = {0009-2673}, url = {://A1995QP06100014}, author = {Endo, K. and Inoue, C. and Kaneda, Y. and Aida, M. and Kobayashi, N. and Chong, D. P.} } @article {2949, title = {ANALYSIS OF THE VALENCE X-RAY PHOTOELECTRON-SPECTRA OF 8 (-CH2-CHR-)(N) AND 2 (-CH2-C(CH3)R-)(N) POLYMERS BY THE SEMIEMPIRICAL HAM/3 MO METHOD USING THE TRIMER MODEL MOLECULES H-(-CH2-CHR-)(3)-H AND H-(-CH2-C(CH3)R-)(3)-H}, journal = {Bulletin of the Chemical Society of Japan}, volume = {67}, number = {11}, year = {1994}, note = {ISI Document Delivery No.: PW118Times Cited: 13Cited Reference Count: 32}, month = {Nov}, pages = {2972-2979}, type = {Article}, abstract = {The valence X-ray photoelectron spectra of ten polymers [(-CH2-CHR-)(n) (R=C6H5, OCH3, COCH3, COOH, COOCH3, OCQCH(3), CONH2, C4H6NO (N-vinylpyrrolidone)) and (-CH2-C(CH3)R-)(n) (R=COOCH3 and CONH2)] were analyzed by a semi-empirical HAM/3 MO method using trimer model molecules [H-(-CH2-CHR-)(3)-H (R=C6H5, OCH3, COCH3, COOH, COOCH3, OCOCH3, CONH2, and C4H6NO (N-vinylpyrrolidone) and H-(-CH2-C(CH3)R-)(3)-H (R=COOCH3 and CONH2)], respectively. The calculated AlK alpha photoelectron spectra were obtained using Gaussian functions of a fixed approximate linewidth (0.10 I-k; I-k=I-k-Delta W, where I-k(,) is the vertical ionization potential of each MO and Delta W is an approximate shift to account for the work-function effects. We assumed that Delta W corresponds to the shift that we must apply before we could compare the calculated spectrum for a single model molecule with the observed spectrum for the solid. The theoretical spectra showed good agreement with the spectra of the polymers, as observed between 0-40 eV.}, keywords = {CLUSTER-EXPANSION, CO2, ENERGY-LEVELS, HAM-3, IONIZATION SPECTRA, N2O, POLYOXYMETHYLENE, WAVEFUNCTION, XPS SPECTRA}, isbn = {0009-2673}, url = {://A1994PW11800012}, author = {Aida, M. and Kaneda, Y. and Kobayashi, N. and Endo, K. and Chong, D. P.} }