Rates of processes initiated by pulsed laser production of F atoms in the presence of HCl, CH₄, and CF₃H

Abstract

Time-resolved vibrational chemiluminescence from HF has been recorded following the production of F atoms by the pulsed laser photolysis (A = 266 nm) of F2 in the presence of HCI, CHI, and CF3H. In the first two cases, experiments have been conducted by observing emission from HF(v = 3) at four temperatures from 295 to 139 K. Rate constants have been determined over this range of temperature for the reactions of F atoms with HC1 and CH4 and of CH3 radicals with F2, and for the relaxation of HF(v = 3) by HC1 and CH4. The reaction of F atoms with CF3H is slower than those with HCl and CH4 and measurements on the emission from HF(v = 2) have been used to infer rate constants for reaction and relaxation only a t 295 K.

Accurate quantum wave packet calculations for the F + HCl → Cl + HF reaction on the ground 12A′ potential energy surface

“…The title reaction has been the subject of many theoretical [1][2][3][4][5][6][7][8][9] and experimental [10][11][12] studies. Experimentalists, have focused on the determination of thermal rate constants.…”

“…Experimentalists, have focused on the determination of thermal rate constants. Wurzberg et al 10,11 and Moore et al 12 measured absolute rate constants in the temperature range 195-373 K and 195-294 K, respectively, using laser photolysis techniques. The measured thermal rate constants were found to follow a non-Arrhenius behavior over the studied temperature range.…”

Semirigid vibrating rotor target model for atom-polyatom reactions: Application to F+CH4→CH3+HF

“…6 shows comparison of our calculated rate constant with the experimental results [19] and with the dynamics calculation by Corchado and EspinosaGarcia on the MJ1 PES [2,3] , using TST-CDSCSAG method and ICVT-CDSCAG method, separately. Wagner et al [4,15,19,25,42] reported the Arrhenius expression 4 F+CH k =5.5×10 −10 exp(−579/T)cm 3 /(molecule −1 s −1 ) for the temperature range of 253-352 K [4,25] . Moore, Smith and Stewart [19] reported recently a rather unusual temperature dependence.…”

“…Wagner et al [4,15,19,25,42] reported the Arrhenius expression 4 F+CH k =5.5×10 −10 exp(−579/T)cm 3 /(molecule −1 s −1 ) for the temperature range of 253-352 K [4,25] . Moore, Smith and Stewart [19] reported recently a rather unusual temperature dependence. Our results exhibit a linear dependence over the whole temperature range.…”

“…The resolved quantum state dynamics of the title reaction has been investigated based on direct absorption of a high resolution infrared (IR) probe laser under crossed supersonic jet conditions [12] . The importance of the reaction has prompted a large number of studies of the rate constants for this reaction, collectively spanning the temperature range of 180-800 K [12][13][14][15][16][17][18][19][20][21] . The first study under low pressure conditions of the F+CH 4 product energy distribution was performed by Nazar and Polanyi [22] , followed by Setser, Heydtmann [23] , and co-workers.…”