@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 {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 {1083,
	title = {Augmenting basis set for time-dependent density functional theory calculation of excitation energies: Slater-type orbitals for hydrogen to krypton},
	journal = {Molecular Physics},
	volume = {103},
	number = {6-8},
	year = {2005},
	note = {ISI Document Delivery No.: 918XQTimes Cited: 23Cited Reference Count: 25},
	month = {Mar-Apr},
	pages = {749-761},
	type = {Article},
	abstract = {Attention is given to the dual nature of the time-dependent density functional theory approach for predicting excitation spectra, namely its theoretical basis in dynamic polarizability and its practical implementation in computer programs as a single configuration interaction. A procedure for generating diffuse functions to be added to standard Slater-type orbital basis sets for H to Kr is proposed and tested on ten close-shell molecules. The database for comparing the performance of standard and augmented basis sets consists of the 15 lowest transitions to valence and Rydberg-like states for each of the molecules. The results of this computational study are very encouraging. The addition of new augmenting functions improves the performance of standard basis sets significantly. For example, the new augmented TZP basis set, about the same size as the standard TZ2P set (and considerably smaller than the large QZ4P set), led to an average absolute deviation of 150 predicted excitation energies of only 0.12 eV from those obtained with the very large basis set called QZ3P-3DIFFUSE, compared to 0.83, 0.79, and 0.19 eV, for the standard TZP, TZ2P, and QZ4P sets, respectively. Similar augmenting functions for Gaussian-type orbital basis sets for H to Kr are also suggested.},
	keywords = {(HYPER)POLARIZABILITIES, BEHAVIOR, EXCHANGE-CORRELATION POTENTIALS, HARTREE-FOCK ORBITALS, INDUCED POLARIZATION FUNCTIONS, LOCAL-DENSITY, POLARIZABILITIES, SHAPE CORRECTIONS, STATES},
	isbn = {0026-8976},
	url = {<Go to ISI>://000228583300003},
	author = {Chong, D. P.}
}
@article {1051,
	title = {Transferable local pseudopotentials derived via inversion of the Kohn-Sham equations in a bulk environment},
	journal = {Phys. Rev. B},
	volume = {69},
	number = {12},
	year = {2004},
	note = {ISI Document Delivery No.: 818QGTimes Cited: 22Cited Reference Count: 142},
	month = {Mar},
	pages = {125109},
	type = {Review},
	abstract = {<p>The lack, of accurate transferable local pseudopotentials represents one of the remaining, barriers to the. general application of orbital-free density functional theory (OF-DFT, a linear scaling technique). Here we report a method to generate high quality ab initio local pseudopotentials (LPS\&rsquo;s) for use in condensed matter DFT calculations. We exploit the first Hohenberg-Kohn theorem, which states that the external potential is, one-to-one mapped to the ground-state electron density. By employing a scheme for inverting the Kohn-Sham (KS) equations due to Wang and Parr, we iteratively solve for the KS effective potential v(eff)(KS)(r) until it reproduces a target density. From v(eff)(KS)(r) we derive a global LPS for the entire system. This global LPS is then further decomposed to obtain an atom-centered LPS. We show that LPS\&rsquo;s,derived from bulk environments are substantially more transferable than those derived from atoms alone. In KS-DFT tests on Si, we show that this bulk-derived LPS can reproduce accurately phase orderings predicted by nonlocal pseudopotentials for both metallic and semiconducting phases. We then tested this LPS in OF-DFT calculations on Si crystals, where we demonstrate that this bulk-derived LPS (BLPS), combined with a linear-response-based kinetic energy density functional with a density-dependent kernel, correctly predicts a diamond structure ground state for Si in an OF-DFT calculation. Other bulk properties, such as defect formation energies and transition pressures are also presented as tests of this BLPS. This approach for deriving LPS\&rsquo;s isolates much of the remaining error in OF-DFT to the kinetic energy density functional, providing means to test new functionals as they become available.</p>},
	keywords = {CORRECT ASYMPTOTIC-BEHAVIOR, ELECTRONIC-STRUCTURE CALCULATIONS, ENERGY-DENSITY FUNCTIONALS, EXCHANGE-CORRELATION POTENTIALS, GROUND-STATE GEOMETRIES, INITIO MOLECULAR-DYNAMICS, KINETIC-ENERGY, NORM-CONSERVING PSEUDOPOTENTIALS, THOMAS-FERMI APPROXIMATION, WAVE-FUNCTIONS},
	isbn = {1098-0121},
	url = {<Go to ISI>://000221259000035},
	author = {Zhou, B. J. and Wang, Y. A. and E. A. Carter*}
}
@article {350,
	title = {Interpretation of the Kohn-Sham orbital energies as approximate vertical ionization potentials},
	journal = {Journal of Chemical Physics},
	volume = {116},
	number = {5},
	year = {2002},
	note = {ISI Document Delivery No.: 514CGTimes Cited: 203Cited Reference Count: 81},
	month = {Feb},
	pages = {1760-1772},
	type = {Article},
	abstract = {Theoretical analysis and results of calculations are put forward to interpret the energies -epsilon(k) of the occupied Kohn-Sham (KS) orbitals as approximate but rather accurate relaxed vertical ionization potentials (VIPs) I-k. Exact relations between epsilon(k) and I-k are established with a set of linear equations for the epsilon(k), which are expressed through I-k and the matrix elements epsilon(k)(resp) of a component of the KS exchange-correlation (xc) potential v(xc), the response potential v(resp). Although -I-k will be a leading contribution to epsilon(k), other I-jnot equalk do enter through coupling terms which are determined by the overlaps between the densities of the KS orbitals as well as by overlaps between the KS and Dyson orbital densities. The orbital energies obtained with "exact" KS potentials are compared with the experimental VIPs of the molecules N-2, CO, HF, and H2O. Very good agreement between the accurate -epsilon(k) of the outer valence KS orbitals and the corresponding VIPs is established. The average difference, approaching 0.1 eV, is about an order of magnitude smaller than for HF orbital energies. The lower valence KS levels are a few eV higher than the corresponding -I-k, and the core levels some 20 eV, in agreement with the theoretically deduced upshift of the KS levels compared to -I-k by the response potential matrix elements. Calculations of 64 molecules are performed with the approximate v(xc) obtained with the statistical averaging of (model) orbitals potentials (SAOP) and the calculated epsilon(k) are compared with 406 experimental VIPs. Reasonable agreement between the SAOP -epsilon(k) and the outer valence VIPs is found with an average deviation of about 0.4 eV. (C) 2002 American Institute of Physics.},
	keywords = {ASYMPTOTIC-BEHAVIOR, DENSITY-FUNCTIONAL THEORY, DERIVATIVE DISCONTINUITIES, ELECTRON BINDING-ENERGIES, EXCHANGE-CORRELATION POTENTIALS, HE(II), LOCAL POTENTIALS, MODEL POTENTIALS, ORGANIC-MOLECULES, PHOTOELECTRON-SPECTRA, STATISTICAL AVERAGE},
	isbn = {0021-9606},
	url = {<Go to ISI>://000173418600003},
	author = {Chong, D. P. and Gritsenko, O. V. and Baerends, E. J.}
}
@article {3020,
	title = {ASSESSMENT OF KOHN-SHAM DENSITY-FUNCTIONAL ORBITALS AS APPROXIMATE DYSON ORBITALS FOR THE CALCULATION OF ELECTRON-MOMENTUM-SPECTROSCOPY SCATTERING CROSS-SECTIONS},
	journal = {Physical Review A},
	volume = {50},
	number = {6},
	year = {1994},
	note = {ISI Document Delivery No.: PX179Times Cited: 122Cited Reference Count: 122Part A},
	month = {Dec},
	pages = {4707-4728},
	type = {Review},
	keywords = {BAND-GAPS, BINDING-ENERGY, DIPOLE-MOMENT, ENERGIES, EXCHANGE-CORRELATION POTENTIALS, HARTREE-FOCK LIMIT, IONIZATION-POTENTIALS, LOCAL-DENSITY, OUTER-VALENCE IONIZATION, QUASIPARTICLE, SPECTRA, VERTICAL, WAVE-FUNCTIONS},
	isbn = {1050-2947},
	url = {<Go to ISI>://A1994PX17900032},
	author = {Duffy, P. and Chong, D. P. and Casida, M. E. and Salahub, D. R.}
}
@article {6979,
	title = {SIMPLIFIED GREEN-FUNCTION APPROXIMATIONS - FURTHER ASSESSMENT OF A POLARIZATION MODEL FOR 2ND-ORDER CALCULATION OF OUTER-VALENCE IONIZATION-POTENTIALS IN MOLECULES},
	journal = {Physical Review A},
	volume = {44},
	number = {9},
	year = {1991},
	note = {ISI Document Delivery No.: GP388Times Cited: 5Cited Reference Count: 81},
	month = {Nov},
	pages = {5773-5783},
	type = {Article},
	abstract = {Ab initio methods for calculating the binding-energy spectra of large molecules have traditionally been restricted to primarily either Koopmans{\textquoteright}s theorem or the density-functional transition-orbital method. The limitations of the former are well known, and the density-functonal "band-gap problem" has led to a further realization of intrinsic difficulties with the latter. An increasingly popular alternative to these two methods is to seek a simple approximation for the Green-function self-energy. The Green-function self-energy is the optical potential seen by a scattering particle (hole). As such, the dominant many-body effects contributing to the self-energy result from polarization of the charge density at energies below the first excitation energy of the target molecule (quasiparticle regime), as well as excitations of the target at higher energies. The physical importance of polarization effects is apparent in Hedin{\textquoteright}s GW approximation, which treats the self-energy as a product of the Green function (G) and a screened interaction (W) that can be calculated (essentially) from the time-dependent linear response of the charge density. In the present paper, we examine the contribution of polarization to the usual second-order Green-function (GF2) approximation with respect to the calculation of outer-valence ionization potentials in small molecules. A simplified version (GW2) of the GW approximation is found to be an acceptable substitute for the GF2 approximation, provided a self-interaction correction is included to prevent an electron from polarizing itself. Polarization effects are further analyzed using the Coulomb-hole and screened-exchange (COHSEX) and modified-COHESEX (M-COHSEX) approximations. A second-order version (M-COHSEX2) of the M-COHSEX approximation is used to examine the origin of the incorrect ordering by Koopmans{\textquoteright}s theorem of the first three ionization potentials of the nitrogen molecule in terms of static polarization and retardation effects. Finite-basis-set errors are also explored. Although higher-order Green-function approximations must be examined before drawing final conclusions, we believe that the present work provides preliminary evidence that suitably modified versions of time-dependent density-functional, dielectric-function-based self-energy approximation can be useful for molecules.},
	keywords = {BAND-GAPS, COULOMB-HOLE, EXCHANGE-CORRELATION POTENTIALS, HARTREE-FOCK, KOOPMANS THEOREM, MANY-BODY THEORY, PI-ELECTRON, pseudospectral method, SCREENED-EXCHANGE, SELF-ENERGY OPERATORS, SYSTEMS},
	isbn = {1050-2947},
	url = {<Go to ISI>://A1991GP38800053},
	author = {Casida, M. E. and Chong, D. P.}
}
