Ground states of linear molecules: Dissociation energies and dipole moments in the hartree-fock approximation

Dipole moments of a series of radicals, OH, NO, NS, SF, SO, PO, ClO, CN, LiO, NO2, and ClO2 were calculated by the Coupled Cluster CCSD(T) method with the single determinant restricted open shell Hartree-Fock (ROHF) reference. For all molecules theoretical dipole moments were carefully compared to experimental values. The size and the quality of the basis set were systematically improved. Spin adaptation in the ROHF-CCSD(T) method, largest single and double excitation amplitudes and the T1 diagnostics were considered as indicators in the quality assessment of calculated dipole moments. For most molecules the accuracy within 0.01-0.03 D was readily obtained. For ClO and CN the spin adaptation was necessary - its contribution was as large as 0.03-0.045 D. Large deviation from experiment is observed for OH in its A2Σ+ excited state (0.135 D) and especially for LiO in its 2Π ground state (0.22 D). No indication of the failure of theoretical calculations was found which leads to the conclusion that, even if there is still a space for the improvement of theoretical calculations, experimental values should be reconsidered.

Download Full-text

Ground states of molecules. XXII. Incorporation of partial configuration interaction in MINDO [modified intermediate neglect of differential overlap]/2 and its application to bond dissociation energies and sigmatropic rearrangements

Journal of the American Chemical Society ◽

10.1021/ja00781a020 ◽

1972 ◽

Vol 94 (26) ◽

pp. 9107-9112 ◽

Cited By ~ 28

Author(s):

Richard C. Bingham ◽

Michael J. S. Dewar

Keyword(s):

Configuration Interaction ◽

Ground States ◽

Bond Dissociation Energies ◽

Bond Dissociation ◽

Dissociation Energies ◽

Sigmatropic Rearrangements ◽

Neglect Of Differential Overlap

Download Full-text

Perturbation treatment of the Hartree–Fock equations for the ground states of the boron-like ions

Canadian Journal of Physics ◽

10.1139/p69-091 ◽

1969 ◽

Vol 47 (7) ◽

pp. 699-705 ◽

Cited By ~ 6

Author(s):

C. S. Sharma ◽

R. G. Wilson

Keyword(s):

Ground State ◽

Atomic System ◽

Ground States ◽

Great Accuracy ◽

Second Order ◽

Expectation Values ◽

Third Order ◽

First Order ◽

Hartree Fock ◽

The Third

The first-order Hartree–Fock and unrestricted Hartree–Fock equations for the ground state of a five electron atomic system are solved exactly. The solutions are used to evaluate the corresponding second-order energies exactly and the third-order energies with great accuracy. The first-order terms in the expectation values of 1/r, r, r2, and δ(r) are also calculated.

Download Full-text

DISQUAC characterization of the carbonyl–oxygen interactions in binary liquid organic mixtures containing linear molecules: ketones and a monoether, diether, or triether

Canadian Journal of Chemistry ◽

10.1139/v96-202 ◽

1996 ◽

Vol 74 (10) ◽

pp. 1815-1823 ◽

Cited By ~ 7

Author(s):

J.A. González ◽

J.M. Fernández Martínez ◽

I. García de la Fuente ◽

J.C. Cobos

Keyword(s):

Dipole Moments ◽

Carbonyl Oxygen ◽

Proximity Effects ◽

Interaction Parameters ◽

Good Representation ◽

Model Interaction ◽

Excess Gibbs Energies ◽

Group Contribution Model ◽

Linear Molecules ◽

Oxygen Groups

The available data in the literature on vapour–liquid equilibria, excess Gibbs energies, and excess enthalpies for linear ketones + linear mono- or poly-ether mixtures are examined in terms of the DISQUAC group contribution model. Interaction parameters are reported. The quasichemical interchange coefficients are independent of the compounds in the systems; the dispersive interchange coefficients depend on the intramolecular environment of the carbonyl and (or) oxygen groups. Proximity effects, which seem to lead to an important increase of the interaction parameters, are briefly considered in treating systems including 1-methoxy-2-propanone or dimethyl carbonate molecules. DISQUAC consistently describes the experimental data of the mixtures investigated. The rather good representation obtained for vapour–liquid equilibria at high temperatures is noteworthy. A discussion in terms of effective and reduced dipole moments of binary mixtures containing carbonyl and oxygen groups in the same or different molecules is also presented. Key words: liquids, mixtures, thermodynamics, dipole moments, group contributions.

Download Full-text