@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 = {://000255603100007},
author = {Chong, D. P. and Segala, M. and Takahata, Y. and Baerends, E. J.}
}
@article {1548,
title = {Density functional theory calculation of 2p core-electron binding energies of Si, P, S, Cl, and Ar in gas-phase molecules},
journal = {Journal of Electron Spectroscopy and Related Phenomena},
volume = {151},
number = {1},
year = {2006},
note = {ISI Document Delivery No.: 017GXTimes Cited: 12Cited Reference Count: 40},
month = {Mar},
pages = {9-13},
type = {Article},
abstract = {Density functional theory (DFT) calculations have been performed on the gas-phase 2p core-electron binding energies (CEBEs) of Si and Ar in 145 cases using the following procedure: AEKS (scalar-ZORA + E-xc)/TZP//HF/6-31G(d). Delta E-KS is the difference in the total Kohn-Sham energies of the 2p-ionized cation and the neutral parent molecule calculated by DFT using different exchange-correlation functionals E-xc with triple-zeta polarized basis set, at molecular geometry optimized by HF/6-31G(d), and relativistic effects have been estimated by scalar zeroth-order regular approximation. Among the 26 functionals tested, the form of E-xc giving the best overall performance was found to be the combination of OPTX exchange and LYP correlation functionals. For that functional, the average absolute deviation (AAD) of the 145 calculated CEBEs from experiment is 0.26 cV. There are seven other exchange-correlation functionals that led to AADs of less than 0.30 eV. Some functionals give lower AADs than E-xc=OPTX-LYP for some individual elements. In the case of Si, for example, the combination of either mPW91-PBE or Becke88-Perdew86 led to an AAD of only 0.10 eV for 56 silicon-containing molecules. Another example is the case of the argon atom, for which the choice of E-xc=OPTX-Perdew86 yields a value for CEBE equal to the experimental value. (c) 2005 Elsevier B.V. All rights reserved.},
keywords = {ABSORPTION, ACCURATE, Ar(2p), ARGON, BEHAVIOR, Cl(2p), emission, ESCA, EXCHANGE-ENERGY, GENERALIZED GRADIENT APPROXIMATION, L-shell ionization, P(2p), POTENTIALS, RAY PHOTOELECTRON-SPECTROSCOPY, S(2p), Si(2p), SILICON, XPS},
isbn = {0368-2048},
url = {://000235683200003},
author = {Segala, M. and Takahata, Y. and Chong, D. P.}
}
@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 {1549,
title = {Geometry, solvent, and polar effects on the relationship between calculated core-electron binding energy shifts (Delta CEBE) and Hammett substituent (sigma) constants},
journal = {Journal of Molecular Structure-Theochem},
volume = {758},
number = {1},
year = {2006},
note = {ISI Document Delivery No.: 011GHTimes Cited: 7Cited Reference Count: 27},
month = {Jan},
pages = {61-69},
type = {Article},
abstract = {According to Lindberg et al. there exists an equation Delta CEBE=kappa sigma for substituted benzene derivatives. Core-electron binding energy shift (Delta CEBE) is the difference between the CEBE of a specific carbon in monosubstituted benzene derivatives (C6H5-Z) and in benzene (C6H5-H); K is related to a reaction constant and or is the experimental Hammett substituent constant. The object of the present work is to investigate geometry, solvent, and polar effects on Lindberg{\textquoteright}s equation using theoretically calculated ACEBE. The CEBEs were calculated using DFT within the scheme Delta E-KS (PW86x-PW91c/TZP + C-rel). The geometry has only little effect on the CEBE values. A regression relation between ACEBE and 0, takes the form Delta CEBE = kappa sigma-C with K congruent to 1.17 and C congruent to 0.17. We estimated 69 sigma constants in water that have not been presented in the literature. Theoretical resonance (sigma(R)) and inductive (sigma(I)) effects were calculated using Taft equations. ACEBE (R) and ACEBE (1) effects on ACEBE were also calculated using Taft-like equations. The quality of the correlation to the resonance is better than that to the inductive effect, in water. The regression quality in aqueous organic solvent is poorer than in water in both Lindberg and Taft equations. The solvent effect is greater on the resonance than on the inductive effect. (c) 2006 Elsevier B.V. All rights reserved.},
keywords = {25-DEGREES-C, ACCURATE, BENZENE-DERIVATIVES, benzenes, BENZOIC-ACIDS, CEBE shift, COMPILATION, DENSITY-FUNCTIONAL CALCULATION, DFF, Hammett sigma, IONIZATION, ISOLATED MOLECULES, LEAST-SQUARES, LFER, STRUCTURE-REACTIVITY PARAMETERS},
isbn = {0166-1280},
url = {://000235255700009},
author = {Segala, M. and Takahata, Y. 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 = {://000230527300007},
author = {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 {349,
title = {DFT calculations of core-electron binding energies of the peptide bond},
journal = {Journal of Physical Chemistry A},
volume = {106},
number = {2},
year = {2002},
note = {ISI Document Delivery No.: 513ANTimes Cited: 24Cited Reference Count: 39},
month = {Jan},
pages = {356-362},
type = {Article},
abstract = {Although an efficient DFT method using the generalized transition-state model to calculate core-electron binding energies had been successfully applied to over 200 cases, with an average absolute deviation of only 0.21 eV from experiment, a new DeltaE(KS)(PW86-PW91)/cc-pCVTZ model based on total Kohn-Sham energy difference was recently developed. Not only was the model error-free, but also the average absolute deviation for 32 cases studied was found to be 0.15 eV. In this study, we first confirm the excellent performance of such a DeltaE(KS) approach with 46 new cases, with the result that the average absolute deviation from experiment for the 78 cases remains at 0.15 eV. With such consistent accuracy, this new method is applied to the peptide bond. The model molecules studied in this work include formamide, N-methylformamide, N,N-dimethylformamide, acetamide, N-methylacetamide, N,N-dimethylacetamide, and two model dipeptides, one cyclic and one acyclic. The difference in the computed nitrogen core-electron binding energy between the two model dipeptides is found to be 0.85 eV, several times our average absolute deviation. This may be of interest to other workers studying other aspects of the peptide bond.},
keywords = {AB-INITIO CALCULATIONS, ACCURATE, APPROXIMATION, DENSITY-FUNCTIONAL CALCULATION, DIFFRACTION, DIKETOPIPERAZINE, EXCHANGE-ENERGY, GAS, MOLECULAR-STRUCTURE, ZETA BASIS-SET},
isbn = {1089-5639},
url = {://000173355900019},
author = {Chong, D. P. and Aplincourt, P. and Bureau, C.}
}
@article {469,
title = {Theoretical Auger electron and X-ray emission spectra of CO and H2O by density functional theory calculations},
journal = {Chemical Physics Letters},
volume = {352},
number = {5-6},
year = {2002},
note = {ISI Document Delivery No.: 521CHTimes Cited: 3Cited Reference Count: 33},
month = {Feb},
pages = {511-520},
type = {Article},
abstract = {We propose a new method for analysis of X-ray emission and Auger electron spectra (XES and AES) of molecules involving the valence spectra using density functional theory (DFT) calculations. To obtain the more accurate transition energies and the relative intensities, we use the total-energy difference procedure (DeltaE-KS) for all transition energies, and transform the coefficients in the LCGTO-MO scheme in the DFT to those for the linear combination of the LCGTO-AO scheme. The method is applied to the analysis of valence spectra, XES and AES for CO and H2O molecules. The simulated spectra are in a good agreement with the experimental results. (C) 20021 Published by Elsevier Science B.V.},
keywords = {ACCURATE, APPROXIMATION, BINDING-ENERGIES, MODEL, PHOTOELECTRON-SPECTRA, POLYMERS},
isbn = {0009-2614},
url = {://000173820900032},
author = {Otsuka, T. and Chong, D. P. and Maki, J. and Kawabe, H. and Endo, K.}
}
@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 = {://000165685400007},
author = {Shapley, W. A. and Chong, D. P.}
}
@article {3281,
title = {DENSITY-FUNCTIONAL CALCULATIONS OF FERMI CONTACT HYPERFINE COUPLING PARAMETERS},
journal = {Chemical Physics Letters},
volume = {234},
number = {4-6},
year = {1995},
note = {ISI Document Delivery No.: QK799Times Cited: 29Cited Reference Count: 31},
month = {Mar},
pages = {405-412},
type = {Article},
abstract = {Fermi contact parameters are calculated with a range of one-particle basis sets and functionals. The parameters are determined at all nuclei in the following eleven radicals: C2H3, C2H2F, CH, NH+, NH, OH+, OH, FH, FF-, CN, NO2. Results show that using Becke{\textquoteright}s new three-parameter exchange functional leads to improved agreement with experiment.},
keywords = {ACCURATE, APPROXIMATION, CORRELATED MOLECULAR CALCULATIONS, DOUBLE-RESONANCE, EXCHANGE-ENERGY, GAUSSIAN-BASIS SETS, MAGNETIC-RESONANCE SPECTRUM, optical, SPECTROSCOPY, TRANSITION},
isbn = {0009-2614},
url = {://A1995QK79900022},
author = {Cohen, M. J. and Chong, D. P.}
}