Journal article

Infrared multiphoton energy deposition in chlorodifluoromethane

Energy absorption by CF2HCl from an intense CO2 laser pulse was measured as a function of the laser energy fluence, the temp., the pressure of CF2HCl, and the pressure of Ar bath gas. For collision-free multiphoton absorption, the av. no. of photons absorbed per mol. increases from 2 to nearly 12 when the fluence is increased from 1.6 to 10.9 J-cm-2 at 298 K. Compariosn of absorption and dissocn. data measured under identical conditions indicates relatively wide internal energy distributions produced by the multiphoton excitation. At 3 J-cm-2 the av. no. of photons absorbed per mol. increases with increasing temp. between 300 and 450 K, whereas in the same temp. range at 10.7 J-cm-2, a pronounced max. was found in the absorption near 370 K. In the presence of 1 atm of added Ar, an av. of as many as 100 photons per mol. of CF2HCl can be absorbed as compared to the 18 photons necessary for collisionless dissocn.


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