The collisional quenching of I(52P12) by the molecules H2O, CH3OH, C2H5OH, HCOOH and CH3COOH by time-resolved emission (I(52P12) → I(52P32) + hν, λ = 1.315 μm) following pulsed-laser photolysis
✍ Scribed by I.I. Gonzalez Liz; F. Castano; E. Martinez; M.N. Sanchez Rayo
- Publisher
- Elsevier Science
- Year
- 1991
- Tongue
- English
- Weight
- 576 KB
- Volume
- 55
- Category
- Article
- ISSN
- 1010-6030
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✦ Synopsis
The collisional quenching,of electronically excited iodine atoms, I(5p'('Pin)), by the molecules HzO, CH,OH, C2H50H, HCOOH and CH,COOH was investigated directly in the time domain. I(2P,,2) was generated by the pulsed excimer laser photolysis of C,F,I at A = 248 nm and monitored by time-resolved emission at A = 1.315 pm (I(2P1/2 * I('PSn) + hv). Absolute second-order quenching rate constants (ko), including those for the collisional removal of the excited atom by the dimers (HCOOH)2 and (CH&OOH)2, were obtained for room temperature. The following results were obtained: k, per cm3 mol-' s-l Hz0 (2.1+-0.2)X lo-l2 CHSOH (9.4 * 0.9) x 10 -13 C$H,OH (14.6 & 1.3) x lo-" HCOOH (3.5 kO.3) x 10-13 (HCOOH)* (3.5 & 0.4) x lo-'3 CH,COOH (5.4 f 0.5) x 10-13 (CHQEOOH)~ (5.4~0.6)x10-13 These results indicate that the main route for removal is the electronic energy transfer in the iodine atom to the second vibrationaf level in the O-H stretching mode in each case, via long-range attractive forces, probably involving dipole-quadrupole interaction on collision.