Linewidths and high resolution structure of the benzene 1B2u←1A1g two photon transition by multiphoton ionization–supersonic beam techniques

Abstract

The two photon spectra of the ¹B_2u state of benzene‐h₆ and benzene‐d₆ have been examined in a supersonic molecular beam/multiphoton ionization experiment. The effect of channel three nonradiative decay on the resonance linewidths was followed through energies greater than 6000 cm⁻¹ above the origin, 3000 cm⁻¹ past the fluorescence cutoff region. The linewidth data suggest a leveling off of the channel three broadening at energies greater than T₀₀+6000 cm⁻¹. A new progression in the benzene‐h₆ spectrum was revealed adjacent to the 14¹₀ 1ⁿ₀ progression (n=1 to 5) which had previously been obscured in the rotational envelope of these bands. New structure and well resolved expected structure is seen in the benzene‐d₆ spectrum as the 14¹₀ 1ⁿ₀ progression is followed out to n=5.