Observation of ArHF(3000) and its combination modes by laser-induced fluorescence

Publisher Website
Google Scholar
Abstract
Laser‐induced fluorescence is used to obtain the second overtone spectrum of ArHF. The method exploits intracavity circulating power of a Ti–sapphire ring laser to pump the weakly bound complex generated in a supersonic slit jet from v=0 to v=3. Fundamental (Δv=−1) emission is monitored using an infrared PbS detector. Intense fluorescence allows recording of the rotationally resolved sub‐Doppler spectra of (3000)←(0000), (3100)←(0000), and (3110)←(0000) transitions. We determine vibrational band origins of ν0=11 339.034 cm−1, 11 412.438 cm−1, 11 422.378 cm−1 and rotational constants of B=0.103 30 cm−1, 0.102 76 cm−1, 0.101 18 cm−1 for the (3000), (3100), and (3110) bands, respectively. Both the band origins and the rotational constants indicate that the weak Ar–HF van der Waals bond is strengthened as the HF stretch is vibrationally excited to higher states. All the observations are in near perfect accord with extrapolations of related constants in the HF stretching states of v=0–2.