Studies of low-frequency intermolecular hydrogen-bonded vibrations using a continuous supersonic slit jet mid-infrared quantum cascade laser spectrometer

摘要

Rovibrational manifolds in low frequency intermolecular vibrations of prototypical hydrogen-bonded interactions OC-HX (X = F, Cl, CN) are reported using a near infrared quantum cascade cw supersonic jet spectrometer. (i) OC-HCl is studied to evaluate future capabilities of the QCL spectrometer. (ii) Analysis of OC-HF demonstrates applicability to vibrations greater than 80 cm ~(-1) above the ground state. ν51 band origins in OC- ~1H ~(35)Cl and OC- ~1H ~(19)F are 48.9944(2) and 81.96825(12) cm ~(-1) respectively. (iii) The corresponding intermolecular ν71 band origin of OC-HCN is 34.63742(18) cm ~(-1) and its corresponding rovibrational spectrum made available for attempted detection in interstellar space. Analysis of ν _2, ~(ν2)+ν71- ν71, ~(ν2)+ν71, and ~(ν2)+ν61 vibrations in OC-HCN also enables generation of its 5-dimensional semi-empirical intermolecular potential. Structural and other properties of OC-HCN are then compared with corresponding properties predicted using morphed potentials for the homologous series OC-HX (X = F, Cl, Br, I). These results permit investigation of blue shifts in OC vibrations for this homologous series.