Infrared double resonance of SF6 with a tunable diode laser. III. Observations of 2ν3←ν3 transitions and collisional relaxation in v3=1

Abstract

The detailed spectroscopy and transition dipole moments of the 2ν3←ν3 transition in SF6 have been investigated by high-resolution infrared double-resonance spectroscopy. The calculated transition frequencies are found to be reliable to within ±0.003 cm−1; in addition, we find that both the l=0←1 and ν3=l=2←1 components of the 2ν3←ν3 transition carry comparable oscillator strength, and that mixing of R states becomes appreciable in 2ν3. The net relaxation rates into depleted levels of the ground vibrational state, and out of laser-populated levels of ν3, are approximately equal to each other (pτ≃35 ns Torr for both). There appear to be no restrictions on relaxation among fine-structure levels in the ground vibrational state; however, initial relaxation out of specified J levels in ν3 appears to involve a limited set of final states which may possibly belong to a vibrational level other than ν3.