Potential energy surface and rovibrational spectrum of He-N_2O dimer

摘要

Symmetry-adaptedperturbation theory (SAPT) calculations were performed to determine a two-dimensional potential for the interaction of the helium atom with the nitrous oxide molecule.For selectedgeometries,correlated supermolecular calculations were used to verify SAPT data.the ab initio interaction enegies were fitted toan analytic function and rovibrational energy levels of He-N_2O were computed on the resultign surface.Extensive comparisons were made with a literature ab initio He-CO_2 potential and rovibrational states in order to rationalize the counterintuitive observations concerning spectra of N_2O and CO_2 in superfluid helium nanodroplets.We conjecture that the greater reduction of the N_2O and CO_2 in superfluid helium nanodroplets.We conjecturehtat the greater reduction of the N_2O and CO_2 in superfluid helium nanodroplets.We conjecuture that the greater reduction of the N_2O rotational constant than that of CO_2 is related to the greatr potential depth in the former case and the resulting greater probability of attaching helium atoms.An additional factor could be that th esecondary minimum on the O side of N_2O is 30% deeper than the linear minima in the case of CO_2.As a by-product of this work,accurate multipole moments of N_2O have been computed.The quadrupole,octupole,and hexadecapole moments are significantly different from experimented.the quadrupole,octupole,and hexadecapole moments of N_2O is 30% deeper than the linear minima in the case of CO_2.As a by-product of this work,accurate multiole moments of N_2O have been computed.The quadrupole,octupole,and hexadecapole moments are significantly different from experimental values and are probably more accurate than the latter.