Direct observation of nitrogen monofluoride(x) using laser-induced fluorescence: kinetics of the (nitrogen monofluoride)3.SIGMA.- ground state

Abstract

The gas-phase kinetics of the NH(X{sup 3}{Sigma}{sup {minus}}) ground-state radical have been investigated by direct observation. NF(X{sup 3}{Sigma}{sup {minus}}) was produced from the KrF laser photolysis of NF{sub 2} and was directly monitored in the gas-phase by use of laser-induced fluorescence (LIF) via the NF b{sup 1}{Sigma}-X{sup 3}{Sigma}{sup {minus}} transition. The extremely hot nascent NF(X{sup 3}{Sigma}{sup {minus}}) vibrational distribution (T{sub vib} = 2350 K) was exploited to investigate vibrational relaxation with CO{sub 2} and SF{sub 6}. While CO{sub 2} proved to be inefficient for NF(X) vibrational relaxation (k{sub 1-0} = 3.7 {times} 10{sup {minus}14} cm{sup 3}/(molecule{center dot}s)), SF{sub 6} is a rapid quencher (k{sub 1-0} = 1.2 {times} 10{sup {minus}12} cm{sup 3}/(molecule{center dot}s)). Information on rotational relaxation of NF(X{sup 3}{Sigma}{sup {minus}}) was also obtained. The NF ground state is seen to be removed by reaction with NF{sub 2} with a rate coefficient of 2.0 {times} 10{sup {minus}12} cm{sup 3}/(molecules{center dot}s). The NF(X) + NF(X) {yields} N{sub 2} + 2F rate coefficient is estimated to be < 5 {times} 10{sup {minus}12} cm{sup 3}/(molecule{center dot}s), much slower than previously thought.