Rapid Estimation of Zero-Point Energies of Molecules Using Hartree−Fock Atomic Partial Charges

2003 ◽  
Vol 107 (11) ◽  
pp. 1833-1839 ◽  
Author(s):  
Adrienn Ruzsinszky ◽  
Sándor Kristyán ◽  
József L. Margitfalvi ◽  
Gábor I. Csonka
Keyword(s):  
Zero Point ◽  
Rapid Estimation ◽  
Hartree Fock ◽  
Partial Charges

FISSION HALF LIVES OF FERMIUM ISOTOPES WITHIN SKYRME HARTREE-FOCK-BOGOLIUBOV THEORY

2011 ◽  
Vol 20 (02) ◽  
pp. 557-564 ◽  
Author(s):  
A. BARAN ◽  
A. STASZCZAK ◽  
W. NAZAREWICZ
Keyword(s):  
Ground State ◽  
Spontaneous Fission ◽  
Zero Point ◽  
Nuclear Fission ◽  
Point Energy ◽  
Generator Coordinate Method ◽  
Hartree Fock ◽  
Bogoliubov Theory ◽  
Generator Coordinate ◽  
Fission Barriers

Nuclear fission barriers, mass parameters and spontaneous fission half lives of fermium isotopes calculated in a framework of the Skyrme Hartree-Fock-Bogoliubov model with the SkM* force are discussed. Zero-point energy corrections in the ground state are determined for each nucleus using the Gaussian overlap approximation of the generator coordinate method and in the cranking formalism. Results of spontaneous fission half lives are compared to experimental data.

Experimental and Theoretical Studies of Rotational Barriers in Aceto-, N-Methylaceto- and N-Phenylacetohydroxamic Acid

2001 ◽  
Vol 66 (1) ◽  
pp. 99-108 ◽  
Author(s):  
David A. Brown ◽  
Laurence P. Cuffe ◽  
Geraldine M. Fitzpatrick ◽  
Noel J. Fitzpatrick ◽  
William K. Glass ◽  
...  
Keyword(s):  
Gas Phase ◽  
Density Functional ◽  
Theoretical Calculations ◽  
Zero Point ◽  
Density Functional Theory Calculations ◽  
Point Energy ◽  
Hartree Fock ◽  
Barrier Heights ◽  
Rotational Barriers ◽  
Moller Plesset

Experimental and theoretical calculations for the E and Z forms of aceto-, N-methylaceto- and N-phenylacetohydroxamic acid are reported. The experimental method was NMR spectroscopy, while the computational methods included Hartree-Fock, Møller-Plesset and density functional theory calculations, with and without solvation, using either the Onsager or Tomasi's PCM method. In all calculations zero point energy corrections were included. The computed results when compared with the experimental ones show that, irrespective of the method used, the differences in the rotational barriers, ∆(E-TS) and ∆(Z-TS), are slight and below the 3 kcal mol-1 limit of the theoretical methods. In general the results using the PCM method were worse than the ones obtained from gas phase calculations or using the Onsager method, even though the PCM method is computationally most expensive. The calculations show, using either the Hartree-Fock or the B3LYP approach, that considering solvation using the Onsager method improves agreement with the experiment results. The calculated barrier heights, excluding the PCM method, agree broadly with the experimental results. Thus using the Onsager approach or gas phase calculations adequate results for barrier heights, but not for relative differences, were obtained.

Gaussian-3X (G3X) theory: Use of improved geometries, zero-point energies, and Hartree–Fock basis sets

2001 ◽  
Vol 114 (1) ◽  
pp. 108 ◽  
Author(s):  
Larry A. Curtiss ◽  
Paul C. Redfern ◽  
Krishnan Raghavachari ◽  
John A. Pople
Keyword(s):  
Zero Point ◽  
Basis Sets ◽  
Hartree Fock ◽  
Theory Use

scholarly journals Simplistic calculation of the tunneling splittings for proton transfer in malonaldehyde and formic acid dimer using the one-dimensional Schrödinger equation

2021 ◽  
Author(s):  
Denis S. Tikhonov
Keyword(s):  
Schrödinger Equation ◽  
Proton Transfer ◽  
Formic Acid ◽  
Schrodinger Equation ◽  
Zero Point ◽  
Basis Set ◽  
One Dimensional ◽  
Hartree Fock ◽  
Tunneling Splittings ◽  
Complete Basis Set

Abstract In this manuscript we present an approach for computing tunneling splittings for large amplitude motions. The core of the approach is a solution of an effective one-dimensional Schrödinger equation with an effective mass and an effective potential energy surface composed of electronic and harmonic zero-point vibrational energies of small amplitude motions in the molecule. The method has been shown to work in cases of three model motions: nitrogen inversion in ammonia, single proton transfer in malonaldehyde, and double proton transfer in the formic acid dimer. In the current work we also investigate the performance of different DFT and post-Hartree-Fock methods for prediction of the proton transfer tunneling splittings, quality of the effective Schrödinger equation parameters upon the isotopic substitution, and possibility of a complete basis set (CBS) extrapolation for the resulting tunneling splittings.

scholarly journals A simplistic computational procedure for tunneling splittings caused by proton transfer

2021 ◽  
Author(s):  
Denis S. Tikhonov
Keyword(s):  
Schrödinger Equation ◽  
Proton Transfer ◽  
Schrodinger Equation ◽  
Zero Point ◽  
Computational Procedure ◽  
Basis Set ◽  
Hartree Fock ◽  
Tunneling Splittings ◽  
Complete Basis Set ◽  
Large Amplitude Motions

AbstractIn this manuscript, we present an approach for computing tunneling splittings for large amplitude motions. The core of the approach is a solution of an effective one-dimensional Schrödinger equation with an effective mass and an effective potential energy surface composed of electronic and harmonic zero-point vibrational energies of small amplitude motions in the molecule. The method has been shown to work in cases of three model motions: nitrogen inversion in ammonia, single proton transfer in malonaldehyde, and double proton transfer in the formic acid dimer. In the current work, we also investigate the performance of different DFT and post-Hartree–Fock methods for prediction of the proton transfer tunneling splittings, quality of the effective Schrödinger equation parameters upon the isotopic substitution, and possibility of a complete basis set (CBS) extrapolation for the resulting tunneling splittings.

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