Showing papers by "Bogumił Jeziorski published in 2000"

On the optimal choice of monomer geometry in calculations of intermolecular interaction energies: Rovibrational spectrum of Ar–HF from two- and three-dimensional potentials

Abstract: Alternatives to using a full-dimensional interaction-potential energy surface and performing a complete dynamics on that surface have been examined for the Ar–HF van der Waals complex. We have employed a symmetry-adapted perturbation theory potential including the dependence on the H–F internuclear distance r. This potential was used to obtain a reference rovibrational spectrum of Ar–HF from the complete three-dimensional dynamics calculations. From the three-dimensional surface we have generated several two-dimensional potentials: the vibrationally averaged potential and the potentials obtained by fixing r at its equilibrium value re and at the vibrationally averaged distances 〈r−2〉−1/2, 〈r〉, 〈r2〉1/2, and 〈r3〉1/3. For all two-dimensional potentials obtained in this way the rovibrational spectra have been computed and compared with the reference spectrum. We have found that the potential obtained by setting r=〈r〉 performs much better than that corresponding to r=re. The spectrum closest to the reference o...

Density shift and broadening of transition lines in antiprotonic helium

Abstract: The density shift and broadening of the transition lines of antiprotonic helium have been evaluated in the impact approximation using an interatomic potential calculated ab initio with the symmetry-adapted perturbation theory. The results help to remove an uncertainty of up to 10 ppm in the laser spectroscopy data on antiprotonic helium and are of importance in experimental tests of bound state QED and CPT invariance.