Wyniki wyszukiwania - BazTech

Ograniczanie wyników

2 Polish Journal of Chemistry

2 1998

Znaleziono wyników: 2

Liczba wyników na stronie

Wyniki wyszukiwania

Wyszukiwano:
w słowach kluczowych: HeH(+)

Sortuj według:

Ogranicz wyniki do:

The ground state of (He-H-He)(+) from correlated ab initio calculations

Komasa J., Rychlewski J.

Polish Journal of Chemistry

1998

Vol. 72, nr 7S

1353-1360

He2H(+) ion in its ground state is studied by means of ab initio methods taking into account the electron correlation. Geometry optimization at the CCSD(T)/cc-pV5Z level of theory has been performed and the potential energy hypersurface scan is presented. The optimum conformation is linear and symmetric with the proton at the He-He midpoint and the He-H distance equal to 1.75 bohr. Stabilization energy with respect to the He2H(+) --- HeH(+) + He dissociation channel has been computed. Additionally, a single point variational calculations with the use of the Exponentially Correlated Gaussian wave functions have been performed. They supply an upper bound to both the total electronic energy (-5.903505 hartree) and the stabilization energy (-13.224 kcal/mol). A comparison of the results from both the perturbational coupled cluster and variational methods is presented.

General formula for shape-resonance life times: the HeH(+) example

Peek J.M.

Polish Journal of Chemistry

1998

Vol. 72, nr 7S

1334-1342

Translational spectroscopy stimulated the investigation of shape resonances in the electronic ground state of HeH(+) a number of years ago. Subsequent spectroscopic studies have increased the accuracy of these experimental data. Theoretical investigations require an extremely accurate potential energy curve over an extended range of internuclear separation. The calculation by Kołos proved invaluable in identifying these states and continues to be the standard to which improvements are added. The accurate characterization of many isolated shape resonances may be necessary so convenient techniques are required. Test functions are often used to create a boundary condition that converts this problem in the continuum to a discrete state calculation. The resulting eigenvalue search is efficient and convenient to automate. The associated widths are usually found by other techniques. It is shown here that the eigenvalue calculation implies a width if one convenient and easily satisfied requirement is met. Two versions of this result are applied to selected experimantal data for HeH(+).