Improving analysis of infrared spectrum of van der Waals complex with theoretical calculation: Applied to Xe–N2O complex

Abstract

A section of infrared spectrum for Xe–N2O has been recorded in the N2O monomer ν1 region, but just 5 rotational resolved lines cannot make an effective rovibrational analysis. To improve the analysis of our observed spectrum for Xe–N2O, a new method is developed based on the bound state calculations with three ab initio potential energy surfaces (PESs). The accuracy of this method is validated by the excellent agreement between theoretical and experimental results for 152 rovibrational transition frequencies with a root mean square deviation of 0.00075cm−1 and spectroscopic parameters with the deviation less than 0.6MHz in the N2O monomer ν3 region. The rotational constants for the excited state are derived with the values of A=12716.1, B=1075.2, C=987.9MHz in the ν1 region of N2O monomer. The band origin of the spectrum is determined to be 1284.8760cm−1 with a red shift of 0.0273cm−1 compared with that of N2O monomer in the ν1 region. The excellent agreement between experimental and theoretical results confirms that this new method is extremely helpful to make a rovibrational analysis for the infrared spectrum of van der Waals complex.