ISSN:
1432-0630
Keywords:
82.50
Source:
Springer Online Journal Archives 1860-2000
Topics:
Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
,
Physics
Notes:
Abstract The mechanism of isotope scrambling was studied for infrared multiphoton dissociation of trifluoromethane-h (CHF3) and-d (CDF3) mixtures by a CO2 TEA laser. The CO2 laser was tuned to the R(14) line of the 001–100 transition, where CDF3 absorbs the light selectively. Although the highly selective decomposition of CDF3 occurred at low partial pressures of CDF3, significant decomposition of CHF3 was also observed with increasing pressure of CDF3. The selectivity (s) was found to depend only on the pressure of CDF3, a resonant molecule, but not on that of CHF3, an off-resonant molecule. The mechanism involving the formation of two kinds of vibrationally excited molecules, unimolecular decomposition (rate constantk 2 ),V-V energy transfer (k 3b), and collisional deactivation leads to the simple relationship,s=1+(k 2 /k 3b)/[CDF3], which can explain qualitatively the observed results. The ratiok 2 /k 3b has values of 20–200 Torr, probably depending on experimental conditions.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00935383
