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-N 2 O has been recorded in the N 2 O monomer ν 1 region, but just 5 rotational resolved lines can not make an effective rovibrational analysis. To improve the analysis of our observed spectrum for Xe-N 2 O, 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 0.00075 cm-1 and spectroscopic parameters with the deviation less than 0.6 MHz in the N 2 O monomer ν 3 region. The rotational constants for the excited state are derived with the values of A = 12716.1, B = 1075.2, C = 987.9 MHz in the ν 1 region of N 2 O monomer. The band origin of the spectrum is determined to be 1284.8760 cm-1 with a red shift of 0.0273 cm-1 compared with that of N 2 O monomer in the ν 1 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.