Direct measurement of the HCl dimer tunneling rate and Cl isotope dependence by farhyphen;infrared laser sideband spectroscopy of planar supersonic jets

摘要

The large amplitude tunneling motion of the HCl dimer has been directly studied with a tunable farhyphen;infrared laser sideband/twohyphen;dimensional free jet expansion spectrometer at hyperfine resolution. Rotationless tunneling rates for the three common chlorine isotopic forms arev(35ndash;35) =463thinsp;979.2(1) MHz,v(35ndash;37)=463thinsp;357.7(1) MHz, andv(37ndash;37)=462thinsp;733.7(3) MHz. Both the rotational constants and hyperfine parameters indicate that the vibrationally averaged structure shows little variation within a given tunneling state, with both HCl bond angles giving an average projection on the ahyphen;axis of 47deg; in all states with resolved hyperfine patterns.