The fundamental vibrational shift of HCl diluted in dense Ar and Kr

Abstract

The fundamental infrared band vibrational shifts of HCl diluted in dense Ar and Kr have been calculated by means of molecular dynamics simulation techniques and compared with the experimental data reported by J. Pérez et al. (J. Chem. Phys. 122, 194507 (2005)). The results have been analyzed along the liquid-vapor coexistence line as in several supercritical states with good agreement between the theoretical and experiemental values.

A Simulation Study of the Fundamental Vibrational Shifts of HCl Diluted in Ar, Kr, and Xe: Anharmonic Corrections Effects

“…In the present work we will study the solvent shifts of HCl also in Ar and Kr and additionally in liquid Xe by considering the non-linear corrections to the solvent shift deduced by Alessi et al [6,7]. Like in the previous work [8] both the diatomic vibration and rotation will be treated with a quantum approach (small system S), while the translational degree of freedom, both of the diatomic and the solvent molecules, will be treated classically (the bath B). Unlike the previous study [8] where the vibration was modeled by means of a cubic anharmonic oscillator, in this work the vibration will be characterized by using a fifth-order Dunham anharmonic oscillator [6,7].…”

“…Like in the previous work [8] we use for such part of the HCl-rare atom potential the model proposed by Marteau el al. [9], which depends only on a fitting parameter, that will be determined by comparing the theoretical and the experimental solvent shifts, at the different thermodynamic states in which the HCl absorption bands were measured.…”

“…We have made a previous study [8] of the vibrational solvent shifts of HCl diluted in Ar and Kr considering the usual linear Buckingham approach. In the present work we will study the solvent shifts of HCl also in Ar and Kr and additionally in liquid Xe by considering the non-linear corrections to the solvent shift deduced by Alessi et al [6,7].…”

“…For the solvent shifts of HCl diluted in dense Ar we have used the same site-site HCl-Ar potential of the previous work [8] (obtained by fitting the site-site potential to the functional form proposed by Holmgren et al [10]), while for HCl diluted in Kr and Xe we have employed the sitesite HCl-rare atom potentials obtained by fitting the sitesite functional form to the accurate potentials proposed by Hutson and Howard [11].…”

“…Like in the previous work [8] both the diatomic vibration and rotation will be treated with a quantum approach (small system S), while the translational degree of freedom, both of the diatomic and the solvent molecules, will be treated classically (the bath B). Unlike the previous study [8] where the vibration was modeled by means of a cubic anharmonic oscillator, in this work the vibration will be characterized by using a fifth-order Dunham anharmonic oscillator [6,7]. Fourth-and fifth-order terms of the intramolecular potential must be considered because they have relevant effects on the anharmonic solvent shift.…”