Refinedabinitiocalculation of the potential energy surface of the Hendash;H2interaction with special emphasis to the region of the van der Waals minimum

摘要

A highly accurateabinitiosurface for the interaction potential of the system HeH2is computed. The method applied is essentially of CI type, but different calculations with different basis sets are performed for (1) the SCF and intrasystem correlations and (2) the intersystem correlation. The former is corrected for basis superposition errors (counterpoise method) and the latter is corrected by inclusion (or simulation) of triply substituted configuration. For either calculation basis saturation tests are performed, a criterion for the interbasis being that it accounts correctly for the van der Waals constants C6,C8and C10and their anisotropies on three successive levels of sophistication. The calculations cover the range fromR=1.5a0(0.8 Aring;) toR=infin; for the Hendash;H2distance, andr=0.9a0to 2.0a0for the Hndash;H distance and the orientation angles 0thinsp;deg;, 45thinsp;deg;, 90thinsp;deg;.