A five-dimensional potential energy surface and predicted infrared spectra for the N_2O-hydrogen complexes

摘要

We present a five-dimensional potential energy surface for the N_2O-hydrogen complex using supermolecular approach with the full counterpoise correction at the coupled-cluster singles and doubles with noniterative inclusion of connected triple level.The normal mode Q_3 for the v_3 antisymmetric stretching vibration of the N_2O molecule was included in the calculations of the potential energies.The radial discrete variable representation/angular finite basis representation method and Lanczos algorithm were employed to calculate the rovibrational energy levels for four species of N_2O-hydrogen complexes (N_2O-para-H_2,-ortho-H_2,-ortho-D_2,and -para-D_2) without separating the inter- and intramolecular vibrations.The calculated band origins are all blueshifted relative to the isolated N_2O molecule and in good agreement with the experimental values.The calculated rotational spectroscopic constants and molecular structures agree well with the available experimental results.The frequencies and line intensities of the rovibrational transitions in the v_3 region of N_2O for the van der Waals ground vibrational state were calculated and compared with the observed spectra.The predicted infrared spectra are consistent with the observed spectra and show that the N_2O-H_2 complexes are mostly a-type transitions while both a-type and b-type transitions are significant for the N_2O-D_2 complexes.