Energy transfer in highly vibrationally excited acetylene: Relaxation for vibrational energies from 6500 to 13 000 cm−1

Abstract

Collisional energy transfer probabilities of highly excited molecules from KCSI. III. Azulene: P(E′,E) and moments of energy transfer for energies up to 40000 cm−1 via self-calibrating experiments

Rovibrational Energy Transfer in the 4νCHManifold of Acetylene Viewed by IR−UV Double Resonance Spectroscopy. 2. Perturbed States withJ= 17 and 18

“…[34][35][36][37] This complements other LIF-detected IR-UV DR studies of C 2 H 2 and its isotopomers in overtone/combination levels with high vibrational energy (G v > 6500 cm -1 ) [38][39][40][41][42][43] and fundamental and lower-energy overtone or combination levels (G v e 6500 cm -1 ). [44][45][46][47][48][49] Several related LIF-detected Raman-UV DR experiments have also been performed.…”

“…Rovibrational perturbations due to anhamonic mixing, lresonance effects, and Coriolis coupling are virtually ubiquitous within the electronic ground state ˜1Σ g + manifold of C 2 H 2 , as is evident from various spectroscopic approaches: IR absorption, 55,57,58,60-63 rovibronic dispersed LIF, 63,64 stimulated emission pumping (SEP), 16,65 optothermally detected laser Stark effect 31 and IR-IR DR, 66 UV LIF-detected IR-UV DR, [38][39][40][41][42][43][44][45][46][47][48][49]67 and rovibrational dispersed LIF. 68 The perturbed character of rovibrational states of C 2 H 2 is significant in more than just the spectroscopic sense or with regard to the above-mentioned tradeoff between IR-dark/ UV-bright and IR-bright/UV-dark character.…”

“…[28][29][30][32][33][34][35][36][37] The IR-UV DR spectrum in trace a is recorded under effectively collision-free conditions with a very small collision number z. (As before, [28][29][30][34][35][36][37]47 values of z are referred arbitrarily to Lennard-Jones collisional rate constants k LJ that are consistent with those adopted by Crim and co-workers; 38,39 for C 2 H 2 /C 2 H 2 self-collisions at 300 K, k LJ ) 16.4 µs -1 Torr -1 ) 5.10 × 10 -10 cm 3 molecule -1 s -1 .) The simple spectrum in trace a comprises the (ν 1 + 3ν 3 )-band R(11) peak; it is accompanied by a single P(13) peak beyond the low-frequency limit of Figure 1, thereby confirming that the UV probe pulse is indeed monitoring the (1 0 3 0 0) 0 J ) 12 rovibrational level.…”

Rotational and vibrational energy transfer in vibrationally excited acetylene at energies near 6560 cm−1

“…Previous studies 22,33,[35][36][37][38] of the total removal rate constants for self-collisions have typically yielded values in the range of (7-11) × 10 −10 cm 3 s −1 , with a tendency for the rate constant to decrease with increasing J i . Removal rate constants have not been reported for (0,1,1,2 0 ,0 0 ), but data for the rotational levels of (1,0,1,0 0 ,0 0 ) are available from the studies of Tobiason, Utz, and Crim.…”

“…Modeling of these experiments, with a view towards optimization and scaling, requires CET data for the ro-vibrational states near 6560 cm −1 . Previously, Crim and co-workers 33,37,38 measured the total population removal rate constants for a sub-set of these levels, but the state-to-state rate constants relevant to the optically pumped laser were not determined. Consequently, we have re-examined the kinetics of RET and vibrational energy transfer (VET) for this energy region using the wellestablished IR pump/ UV probe technique.…”