Temporal evolution and variation of laser optogalvanic signals in the spectra of inert gases

Abstract

We present new studies on the temporal evolution and variation of the laser optogalvanic signals in the spectra of inert gases using commercial hollow cathode lamps in conjunction with a Nd:YAG pumped dye laser system. The behavior of the optogalvanic signals for the transitions following the ΔJ=ΔK=0 and ± 1 dipole selection rules in the jcK-coupling scheme namely mp5(m+1)p[5/2]3, mp5(m+1)p′[3/2]2, mp5(m+1)p[3/2]2, mp5(m+1)p′[1/2]1 and mp5(m+1)p[1/2]1 coupled with mp5(m+1)s[3/2]2 (m=2, 3, 4 and 5 for neon, argon, krypton and xenon, respectively) metastable level have been investigated. An empirical relation is formulated: S(t)=Smin+A(t)exp(−α[I−I0]) which satisfactorily describes the shift of the optogalvanic signal and the change in the population of the upper level as a function of the discharge current. It is observed that the shift in the optogalvanic signal peaks for the ΔJ=ΔK=−1 transitions is larger than that for the ΔJ=ΔK=+1 transitions whereas the signal peaks remain unshifted for the ΔJ=ΔK=0 transitions.