ISSN:
1089-7690
Source:
AIP Digital Archive
Topics:
Physics
,
Chemistry and Pharmacology
Notes:
The effect of temperature on the 385 nm luminescence band emitted by electron-irradiated H2O ice has been determined between 79 and 117 K. From 79 to 101 K, the luminescence intensity did not change greatly with increasing temperature, but fell steeply between 101 and 117 K, paralleling the behavior of trapped OH. Kinetic analysis of the luminescence decay was possible in the 79–103 K region and revealed a long-lived pseudo-first-order decay and a superimposed short-lived decay with respective activation energies of 0.036±0.005 and 0.021±0.005 eV. The long-lived emission is attributed to the migration of H+ to OH− formed from trapped OH, subsequent reaction producing H2O(C 1B1) which emits excimer luminescence when it falls to the dissociative A 1B1 state. This mechanism was tested by using it to derive a kinetic expression which relates the observed temperature dependencies of both the luminescence intensity and the decay rate. This mechanism suggests that the radiolytic yield of OH− in ice is in the vicinity of G(OH−)=0.2/100 eV.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1063/1.461217
