A. Ershov et J. Borysow, DYNAMICS OF OH (X(2)PI, V=0) IN HIGH-ENERGY ATMOSPHERIC-PRESSURE ELECTRICAL PULSED DISCHARGE, Journal of physics. D, Applied physics, 28(1), 1995, pp. 68-74
Time transients of the number density of the hydroxyl radical ground s
tate X(2) Pi (v = 0) formed in the Dc high-energy atmospheric pressure
pulsed discharge were measured by means of laser-induced fluorescence
. The frequency doubled dye laser was tuned to the A(2) Sigma <-- X(2)
Pi (v' = 1 <-- v'' = 0) transition at 282 nm while emission at 309 nm
from A(2) Sigma --> X(2) Pi (v' = 0 --> v'' = 0) band, was observed.
The discharge peak current l(max) varied from 10(-2) to 10 A, and the
time duration was from 500 ns to 50 mu s. The discharge was operated a
t repetition rate of 10 Hz. The population of v'' = 0 of OH reaches th
e steady state within the first 20 mu s of the discharge and its value
is independent on the current for l(max) greater than or equal to 0.2
A. The significant build-up of v'' = 0 state population was observed
after the discharge pulse. The hydroxyl ground state number density re
aches its maximum value approximately 100 mu s after the discharge and
is up to three times larger than during the discharge pulse. This inc
rease of v'' = 0 population is attributed to the vibrational relaxatio
n within X(2) Pi state.