@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 = {<Go to ISI>://000235683200003},
	author = {Segala, M. and Takahata, Y. 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 {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 = {<Go to ISI>://000187364200010},
	author = {Takahata, Y. and Chong, D. P.}
}
@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 = {<Go to ISI>://000173355900019},
	author = {Chong, D. P. and Aplincourt, P. and Bureau, C.}
}
@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 {4501,
	title = {Accurate density-functional calculation of core-electron binding energies by a total-energy difference approach},
	journal = {Journal of Chemical Physics},
	volume = {111},
	number = {21},
	year = {1999},
	note = {ISI Document Delivery No.: 255TCTimes Cited: 34Cited Reference Count: 52},
	month = {Dec},
	pages = {9485-9492},
	type = {Article},
	abstract = {A procedure for calculating core-electron binding energies (CEBEs), based on a total-energy difference approach within Kohn-Sham density functional theory, was investigated. Ten functional combinations and several basis sets (including unscaled, scaled, and core-valence correlated functions) were studied using a database of reliable observed CEBEs. The functionals designed by Perdew and Wang (1986 exchange and 1991 correlation) were found to give the best performance with an average absolute deviation from experiment of 0.15 eV. The scaled basis sets did not perform satisfactorily, but it was found that the core-valence correlated cc-pCVTZ basis functions were an excellent alternative to the cc-pV5Z set as they provided equally accurate results and could be applied to larger molecules. (C) 1999 American Institute of Physics. [S0021-9606(99)30742-X].},
	keywords = {APPROXIMATION, CALCULATIONS, CORRELATED MOLECULAR, EXCHANGE-ENERGY, GAS, GAUSSIAN-BASIS SETS, METHANE, MODEL MOLECULES, POLYACRYLONITRILE, RAY PHOTOELECTRON-SPECTRA, ZETA BASIS-SET},
	isbn = {0021-9606},
	url = {<Go to ISI>://000083685400006},
	author = {Cavigliasso, G. and Chong, D. P.}
}
@article {3276,
	title = {ACCURATE CALCULATION OF CORE-ELECTRON BINDING-ENERGIES BY THE DENSITY-FUNCTIONAL METHOD},
	journal = {Chemical Physics Letters},
	volume = {232},
	number = {5-6},
	year = {1995},
	note = {ISI Document Delivery No.: QE867Times Cited: 67Cited Reference Count: 26},
	month = {Jan},
	pages = {486-490},
	type = {Article},
	abstract = {Using a basis set of atomic natural orbitals of valence triple-zeta plus double polarization quality, the core-electron binding energies (CEBEs) of HF, H2O, N-2 and CO were computed by the deMon density-functional program with a combined functional of Becke{\textquoteright}s exchange (B88) with Perdew{\textquoteright}s correlation (P86). Of four different versions of the transition-state method tested, the unrestricted generalized transition-state (uGTS) model showed most promise. Two other functionals were tested but found to be inferior to the B88/P86 combination. The molecules HCN, CO2 and H2CO were added in the comparative study of basis set convergence. The best procedure found (the uGTS model using B88/P86 functional with Dunning{\textquoteright}s cc-pV5Z basis set) was applied to other molecules. The average deviation from experiment for 20 computed CEBEs is 0.23 eV.},
	keywords = {APPROXIMATION, ATOMS, BASIS-SETS, EXCHANGE-ENERGY},
	isbn = {0009-2614},
	url = {<Go to ISI>://A1995QE86700011},
	author = {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 = {<Go to ISI>://A1995QK79900022},
	author = {Cohen, M. J. and Chong, D. P.}
}
@article {3503,
	title = {Momentum Profiles for Open-Shell Molecules: Studies of the HOMO{\textquoteright}s of NO, O<sub>2</sub>, and NO<sub>2</sub> by Electron Momentum Spectroscopy and SCF, Post-Hartree-Fock and DFT Calculations},
	journal = {Chem. Phys.},
	volume = {201},
	number = {1},
	year = {1995},
	note = {ISI Document Delivery No.: TH205Times Cited: 29Cited Reference Count: 74},
	month = {Dec},
	pages = {1-21},
	type = {Article},
	abstract = {<p>Measurements of the outermost valence electron orbital momentum profiles of the open shell molecules NO, O-2 and NO2 have been obtained using electron momentum spectroscopy (EMS). The presently reported experimental momentum profiles of NO and O-2 display much improved statistics compared with previously published EMS results while the data for the HOMO of NO, is the first reported. In the case of NO, the present measurements are considerably different from previous results and these differences appear to be due to the presence of NO2 impurities in the previous work. The EMS measurements provide a stringent test of basis set effects and the quality of ab initio methods in the description of these open shell systems. The experimental momentum profiles have been compared with theoretical spherically averaged momentum profiles from several basis sets calculated at the level of the target Hartree-Fock approximation (THFA) with a range of basis sets using both unrestricted Hartree-Fock (UHF) and restricted open shell Hartree-Fock (ROHF) methods. Various configuration interaction calculations such as multi-reference singles and doubles configuration interaction (MRSD-CI), averaged coupled pair functional (ACPF) and quasi-degenerate variational perturbation theory (QDVPT) calculations of the full ion-neutral overlap amplitude have also been compared to experiment to investigate the effects of electron correlation and relaxation. The experimental momentum profiles have further been compared to calculations at the level of the target Kohn-Sham approximation (TKSA) using density functional theory (DFT) with the local density approximation and also with gradient corrected exchange-correlation potentials. In addition to momentum profiles, other electronic properties such as total energies, dipole moments, quadrupole moments and values of the electronic spatial extent have been calculated by the various theoretical methods and compared to experimental values.</p>},
	keywords = {CORRELATED WAVEFUNCTIONS, CORRELATION ENERGIES, density, DIPOLE-MOMENT, EXCHANGE-ENERGY, GAUSSIAN-BASIS SETS, NITRIC-OXIDE, VALENCE ORBITALS, VARIATIONAL PERTURBATION-THEORY, WAVE-FUNCTIONS},
	isbn = {0301-0104},
	url = {<Go to ISI>://A1995TH20500001},
	author = {Rolke, J. and Cann, N. and Zheng, Y. and Hollebone, B. P. and C. E. Brion* and Wang, Y. A. and Davidson, E. R.}
}
