Some approximate Kohn—Sham molecular energy formulas

Politzer, Peter; Abu-Awwad, Fakher

doi:10.1080/00268979809483201

Cited by 10 publications

(8 citation statements)

References 49 publications

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“…(18) and its atomic version, Eq. (14); these include estimating the energies of valence electronic charges 30–32 and atoms in molecules 33, deriving relationships between molecular and sums of orbital energies 24, 34, analyzing molecular charge distributions and bonding 35, 36, and estimating energy changes associated with crystal lattice formation 37.…”

Section: Discussion and Summarymentioning

confidence: 99%

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Mini‐invasive strategy in acute coronary syndromes: Direct coronary stenting using 5 Fr guiding catheters and transradial approach

Hamon

Sabatier

Zhao

et al. 2002

Cathet Cardio Intervent

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The purpose of this study was to assess the feasibility and safety of direct coronary stenting in acute coronary syndromes using 5 Fr guiding catheters by transradial approach. A series of 119 patients with an acute coronary syndrome (unstable angina, n = 55; acute myocardial infarction, n = 45; recent acute myocardial infarction, n = 19) explored by transradial approach and eligible for direct stenting were included. A large proportion of patients (52%) was treated during the procedure by platelet IIb/IIIa receptor blockade. Only Medtronic 5 Fr guiding catheters were used in this study. Direct coronary stenting was attempted in all 119 highly selected patients. Failure of direct stenting was observed in only five cases (3.9%) and the stent successfully retrieved in each case in the 5 Fr guiding catheter. In these five cases, balloon predilation was performed and then the stent implanted successfully. Different stents were used: ACS stent (54%), AVE stent (33%), Velocity stent (10%), Nir stent (3%), with diameter ranging from 2.5 to 4 mm. In four cases, the dilation was finally performed using 6 Fr guiding catheters because the backup of the 5 Fr catheter was considered to be too low (3%). No vascular access site complications occurred in this series of patients. We conclude that direct coronary stenting using transradial approach and 5 Fr guiding catheters yields excellent procedural success rate. In the setting of acute coronary syndromes requiring platelet IIb/IIIa receptor blockade or after failure of thrombolysis, this mini-invasive strategy is very attractive because of the low risk of access site complications.

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Section: Discussion and Summarymentioning

confidence: 99%

“…(6), is just a summation over the atomic version, Eq. (5), it seemed natural to try the same approach at the approximate level: This was found to reproduce Hartree–Fock energies to generally within about 1% 21–23, and Kohn–Sham density functional to less than 0.70% 24.…”

Section: Approximate Expressionsmentioning

confidence: 99%

Mini‐invasive strategy in acute coronary syndromes: Direct coronary stenting using 5 Fr guiding catheters and transradial approach

Hamon

Sabatier

Zhao

et al. 2002

Cathet Cardio Intervent

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“…Although the physical meaning of Kohn-Sham ͑KS͒ orbital energies remains a controversial issue in the literature, 50,51 several works provided evidence that DFT can correctly predict electron binding energies. [52][53][54][55][56][57][58][59][60][61] The disagreement between KS electron binding energies predicted by the widely used exchange-correlation functionals and experiment is related to the self-interaction error in DFT. 62 An interesting possibility is to parametrize the exchangecorrelation functional for reproducing experimental electron binding energies.…”

Section: B Density-functional Theory Calculationsmentioning

confidence: 99%

“…62 An interesting possibility is to parametrize the exchangecorrelation functional for reproducing experimental electron binding energies. 53,57 The present approach to study the electronic properties of water is based on the following semiempirical procedure. The modified Perdew-Wang functional ͑MPW1PW91͒ proposed by Adamo and Barone [43][44][45] has been reparametrized to reproduce the electronic properties of the water dimer.…”

Section: B Density-functional Theory Calculationsmentioning

confidence: 99%

The Kohn-Sham density of states and band gap of water: From small clusters to liquid water

Couto¹,

Estácio²,

Cabral³

2005

The Journal of Chemical Physics

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Electronic properties of water clusters (H2O)(n), with n=2, 4, 8, 10, 15, 20, and 30 molecules were investigated by sequential Monte Carlo/density-functional theory (DFT) calculations. DFT calculations were carried out over uncorrelated configurations generated by Monte Carlo simulations of liquid water with a reparametrized exchange-correlation functional that reproduces the experimental information on the electronic properties (first ionization energy and highest occupied molecular orbital-lowest unoccupied molecular orbital gap) of the water dimer. The dependence of electronic properties on the cluster size (n) shows that the density of states (DOS) of small water clusters (n>10) exhibits the same basic features that are typical of larger aggregates, such as the mixing of the 3a1 and 1b1 valence bands. When long-ranged polarization effects are taken into account by the introduction of embedding charges, the DOS associated with 3a1 orbitals is significantly enhanced. In agreement with valence-band photoelectron spectra of liquid water, the 1b1, 3a1, and 1b2 electron binding energies in water aggregates are redshifted by approximately 1 eV relative to the isolated molecule. By extrapolating the results for larger clusters the threshold energy for photoelectron emission is 9.6+/-0.15 eV (free clusters) and 10.58+/-0.10 eV (embedded clusters). Our results for the electron affinity (V0=-0.17+/-0.05 eV) and adiabatic band gap (E(G,Ad)=6.83+/-0.05 eV) of liquid water are in excellent agreement with recent information from theoretical and experimental works.

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“…Moreover, Kohn-Sham orbital energies differ from ionization potentials by a factor of about 2 [23]. Recently, Politzer and Abu-Awwad [27,28] proposed a reparametrization of the Becke-3 hybrid exchangecorrelation functional that predicts orbital energies in good agreement with experimental ionization potentials. In addition, the modified exchange-correlation functional is able to predict other molecular properties of the water molecule (geometry, dipole moments) in good agreement with experiment [28].…”

Section: Introductionmentioning

confidence: 65%

The density of states and band gap of liquid water by sequential Monte Carlo/Quantum mechanics calculations

2004

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Electronic properties of liquid water were investigated by sequential Monte Carlo/Quantum mechanics calculations. The density of states (DOS) and HOMO-LUMO gap (EG) of liquid water have been determined by Hartree-Fock and Density Functional Theory (DFT) calculations. The quantum mechanical calculations were carried out over uncorrelated supermolecular structures generated by the Monte Carlo simulations. The DFT calculations were performed with a modified B3LYP exchange-correlation functional proposed by Abu-Awwad and Politzer which was parametrized to reproduce valence orbital energies in agreement with experimental ionization potentials of the water molecule. We have analyzed the dependence of the DOS and HOMO-LUMO gap on the number of water molecules and on surface effects. Our prediction for E G is 6.5 ± 0.5 eV in good agreement with a recent experimental prediction of 6.9 eV.

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Some approximate Kohn—Sham molecular energy formulas

Cited by 10 publications

References 49 publications

Mini‐invasive strategy in acute coronary syndromes: Direct coronary stenting using 5 Fr guiding catheters and transradial approach

Mini‐invasive strategy in acute coronary syndromes: Direct coronary stenting using 5 Fr guiding catheters and transradial approach

The Kohn-Sham density of states and band gap of water: From small clusters to liquid water

The density of states and band gap of liquid water by sequential Monte Carlo/Quantum mechanics calculations

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