High frequency wavelength modulation cw slit jet diode laser spectrometer for characterizing ground state intermolecular hydrogen bonded vibrations

摘要

A high frequency wavelength modulation near infrared diode laser spectrometer with a cw supersonic slit jet is described that is capable of providing rovibrational data for ground state intermolecular fundamentals in hydrogen bonded complexes. The spectrometer performance is initially characterized by investigation of rovibrational transitions in the v_2 bands of the common isotopomers of the hydrogen bonded dimer (HBr)_2. Analyses of the v_2~+ and v_2~+ - v_5~1 vibrations in the homomolecular dimer (HI)_2 are then used to provide molecular parameters for determination of the intermolecular v_5~1 band of this complex at 14.3216(20) cm~(-1). As a further illustration of the spectrometer performance, rovibrational analysis of the v_2, v_2 + v_5~1 and v_2 + v_5~1 - v_5~1 bands in the heteromolecular complex OC:HI are used to generate molecular parameters for intermolecular fundamentals associated with both a hydrogen bonded form and a van der Waals isomeric form in this dimer. The band origin frequencies of the v_5~1 OC-HI and v_5~1 OC-IH vibrations are determined to be at 25.8917(20) and 28.3100(20) cm~(-1), respectively.