Radiative characteristics of 3p Sigma,Pi; 3d Pi(-),Delta(-) states of H-2 and determination of gas temperature of low pressure hydrogen containing plasmas

For the first time semiempirical data on the radiative transition probabilities for rovibronic transitions between 3p Sigma, Pi; 3d Pi(-), Delta(-) and 2p Sigma, Pi states and radiative lifetimes of upper rovibronic levels of the hydrogen molecule were analysed in detail and presented in a table form useful for applications. The intensities of e(3) Sigma(u)(+), d(3) Pi(u)(+/-) --> a(3) Sigma(g)(+), i(3) Pi(g)(-), j(3) Delta(g)(-) --> c(3) Pi(u) and I-1 Pi(g)(-), J(1) Delta(g)(-) --> C-1 Pi(u) band systems have been measured in d.c. capillary-arc and microwave discharges under pressures of 1-600 Pa and a power input of 1-500 W. It was observed, that recalculated for the ground X(1) Sigma(g)(+) vibronic state, values of rotational temperature, derived from the populations of e(3) Sigma(u)(+), d(3) Pi(u)(+), d(3) Pi(u)(-), j(3) Delta(g)(-) and J(1) Delta(g)(-) states, coincide within 10-20% and may be used for plasma diagnostics. In contrast, the rotational population density distributions in I-1 Pi(g)(-) and i(3) Pi(g)(-) states show abnormal behaviour corresponding to effective temperatures, which are about two times higher. The effect needs further investigations in crossed beams and gas-beam experiments. Copyright (C) 1996 Elsevier Science Ltd