Study of IR multiple-photon absorption (MPA) of CF3Br

Molecular Beam Opto‐thermalStudy of the Multiple‐photonInfrared Excitation of CF3Br

“…The 1074.7 cmpeak can be attributed to both a four-photon v 4 -v 0 transition and a two-photon , 3 --, transition of thermally excited molecules. 33 We do not have enough information to assign the observed peak to a well defined transition but high source temperature data suggest that it is more likely to be due to a two-photon hot transition.…”

“…In the same figure is also drawn the result of a theoretical calculation by Capitelli and co-workers. 33 The theoretical calculations have been carried out by a numerical analysis based on the "heat-bath feed-back" model. 37'38 They calculated the multiple-photon excitation of the molecule as a solution of Bloch equations for the first four discrete levels and of the incoherent master equations for the so-called quasicontinuum.…”

“…The multiple-photon excitation spectrum of CF3Br for 3 different molecular beam temperatures (O 248 K; & 298 K; 1 348 K). The dashed line is the result of a theoretical calculation taken from Ref 33. (Figure lb).…”

“…The laser fluence is set at the fixed value of 0.75 J cm-2. For comparison are shown the results of a cell experiment (A Ref 33. Figure 3a)carried out under similar laser conditions.…”