Simplified Non-Empirical Unrestricted Hartree-Fock Approximation (SUHF) for the Calculation of Electronic Ground State Properties of Molecules with Closed and Open Valence Shells. II. Diatomic Molecules

1993 ◽  
Vol 48 (7) ◽  
pp. 834-840
Author(s):  
Wolfhard Koch ◽  
Klaus Neymeyr ◽  
Markus Pernpointner ◽  
Barbara Schaper ◽  
Klaus Strecker
Keyword(s):  
Ground State ◽  
Diatomic Molecules ◽  
Electronic Ground State ◽  
Basis Sets ◽  
Gaussian Basis Sets ◽  
Atomic Spin ◽  
Hartree Fock ◽  
Total Energies ◽  
Simplified Procedure ◽  
Electronic Ground

Abstract A comparison of numerical Simplified Unrestricted Hartree-Fock (SUHF) results (electronic ground state configurations, total energies, first ionization potentials, atomic charges, atomic spin densities of diatomic molecules) with those of equivalent standard calculations suggests the applicability of the non-empirical but drastically simplified procedure. SUHF may even approach ab initio quality obtained with simple (STO-3G) contracted Gaussian basis sets.

Gaussian basis sets for the atoms from K through Xe

2001 ◽  
Vol 79 (2) ◽  
pp. 121-123 ◽  
Author(s):  
R Centoducatte ◽  
E VR de Castro ◽  
F E Jorge
Keyword(s):  
Key Words ◽  
Ground State ◽  
Basis Sets ◽  
Gaussian Basis Sets ◽  
Hartree Fock ◽  
Generator Coordinate ◽  
Discretization Technique ◽  
Total Energies

An improved generator coordinate Hartree-Fock (IGCHF) method is used to generate Gaussian basis sets for the atoms from K (Z = 19) through Xe (Z = 54). The Griffin-Hill-Wheeler-HF equations are integrated using the integral discretization technique. The ground state HF total energies obtained by us are compared with those calculated with the original GCHF method and with other approaches reported in the literature. The largest difference between our energy values and the corresponding ones computed with a numerical HF method is equal to 6.003 mhartree for Kr (Z = 36).Key words: improved generator coordinate Hartree-Fock method, Gaussian basis sets, total energies.

The Nearly Degenerate Triplet Electronic Ground State Isomers of Lithium Nitroxide

2007 ◽  
Vol 72 (2) ◽  
pp. 129-152 ◽  
Author(s):  
Justin M. Turney ◽  
Henry F. Schaefer
Keyword(s):  
Ground State ◽  
Global Minimum ◽  
Electronic Ground State ◽  
Basis Sets ◽  
Stationary Points ◽  
Mechanical Methods ◽  
State Potential ◽  
Correlation Consistent ◽  
Highly Correlated ◽  
Electronic Ground

The triplet electronic ground state potential energy surface of lithium nitroxide has been systematically investigated using convergent quantum mechanical methods. Equilibrium structures and physical properties for five stationary points (three minima and two transition states) have been determined employing highly correlated coupled cluster theory with four correlation-consistent polarized-valence (cc-pVXZ and aug-cc-pVXZ, X = T and Q) and two core correlation-consistent polarized-valence (cc-pCVXZ, X = T and Q) basis sets. The global minimum, roughly L-shaped Li-O-N, is predicted to lie 6.5 kcal mol-1 below the linear LiON minimum and 2.4 kcal mol-1 below the linear LiON minimum. The barrier to isomerization from the global minimum to LiON was found to be 7.4 kcal mol-1 and with regard to LiNO 6.9 kcal mol-1. The dissociation energies, D0, with respect to Li + NO, have been predicted for all minima and for the global minimum was found to be 34.9 kcal mol-1.

FORBIDDEN TRANSITIONS IN DIATOMIC MOLECULES: I. THE QUADRUPOLE ROTATION–VIBRATION SPECTRUM OF H2

1950 ◽  
Vol 28a (2) ◽  
pp. 144-152 ◽  
Author(s):  
G. Herzberg
Keyword(s):  
Ground State ◽  
Vibration Spectrum ◽  
Diatomic Molecules ◽  
Electronic Ground State ◽  
Forbidden Transitions ◽  
Vibrational Constants ◽  
Electronic Ground

Four lines of the 2–0 band and four lines of the 3–0 band of the quadrupole rotation–vibration spectrum of H2 have been observed and measured using effective absorbing paths of 10 to 50 km. atm. From this spectrum improved values of the rotational and vibrational constants of H2 in its electronic ground state have been obtained.

DETERMINATION OF THE ELECTRONIC GROUND STATE OF MOLECULAR SYSTEMS WITH THE MULTI-CONFIGURATION TIME-DEPENDENT HARTREE–FOCK METHOD

2007 ◽  
Vol 06 (03) ◽  
pp. 563-574 ◽  
Author(s):  
M. NEST
Keyword(s):  
Ground State ◽  
Equations Of Motion ◽  
Electronic Ground State ◽  
Time Dependent ◽  
Molecular Systems ◽  
Hartree Fock ◽  
Time Propagation ◽  
Core Excitations ◽  
Electronic Ground

In this paper, we present progress in the application of the explicitly time-dependent multi-configuration time-dependent Hartree–Fock (MCTDHF) method. The spin–orbitals and equations of motion are expressed in the basis of Gaussian Type Orbitals. MCTDHF is then applied to the calculation of the electronic ground state of various small molecules by imaginary time propagation. We were able to take between four and 12 active electrons into account. We discuss the suitability of a core guess as initial wave function, the possibility to obtain excited states, as well as the consequences of a neglect of core excitations.

ChemInform Abstract: TRIPLET ELECTRONIC GROUND STATE OF TRIMETHYLENEMETHANE

1974 ◽  
Vol 5 (33) ◽  
pp. no-no
Author(s):  
DAVID R. YARKONY ◽  
HENRY F. III SCHAEFER
Keyword(s):  
Ground State ◽  
Electronic Ground State ◽  
Electronic Ground
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