Critically evaluated rate constants for gaseous reactions of several electronically excited species

Abstract

An extensive evaluation is presented of the available gas phase chemical kinetic rate constants for the interac· tions of the low lying electronic states of several atoms and molecules with numerous collision partners. These include the following excited states: C(2 1 D 2 ,2 1 S o ), N(2 2 D31l,5/2, 2 2 P1I1, 3/2), P(32D3/2,51l,32Pl/2,3/2), S(3 1 D 2 ,3 I S 0 ), Se(4 S P o ' 4 1 D 2 ,4 1 S 0 ), Te(53PI,o,51D2,5ISo)' COCa an, a'3I;+,d aA,e 3I;-,A III), CS(a all, A III), OH(A 2I;+), OD(A 2£+), 02(C lE~,C 3A u .A 3I;~,B 3r;~), and S2(a IAg,b lE;,A ar;~,B ar;~). Wherever possible, recommended values are suggested. Much of the data refers only to room temperature. To facilitate the evaluation, colJision·free radiative lifetimes often have been required. These also have been evaluated and are presented. The mechanisms of the interactions and the various potential kinetic channels are discussed. These include such processes as chemical reactions, electronic quenching to the ground electronic state, electronic cross relaxation to an adjacent excited state, and for molecules, vibrational and rotational relaxation processes within the excited state. A complete coverage of the literature published prior to 1978 has been attempted.

A laser-photolysis fragment-fluorescence (LPFF) method for the detection of gaseous nitric acid in ambient air

“…In spite of this precaution, the decaying stray light signal still limits the detection. OH(A) fluorescence is efficiently quenched by almost all gases (Schofield, 1979). In fact, Figure 5 indicates that, due to quenching by air, the emission lifetime is much shorter than about 690 ns, the electronic lifetime of that state (German, 1975).…”

Plasma-Assisted Catalytic Reduction of NOx

“…Because of the large rate constant [32] for reaction (7) and the large concentration of O 2 relative to NO, the N( 2 D) species preferentially reacts with O 2 to produce NO. In a lean-burn exhaust, the production of NO by N( 2 D) will counterbalance the reduction of NO by N( 4 S), thus effectively leaving oxidation as the only pathway for NO conversion.…”

Nonequilibrium excitation of internal molecular degrees of freedom in the shock layer during hypersonic flight

“…Electronically excited atoms N(2P, 2D), O( ~ S, 1D), which can be produced in quenching of the excited molecules, are also rapidly quenqhed in collisions with components of the partially dissociated air (Schofield 1978(Schofield , 1979Slovetsky 1980). Therefore, for real conditions of RSV's flight the formation of electronically excited states N2(ASS~+), O2(A3.~, A'3Au, cl.~u), NO(B2H, a4H, A2S+), O(1S), N(2P), O(ID), N(2D) is allowed to be neglected.…”

“…Ni, Cu under low temperatures (Halstead et al 1985)). Moreover, these highexcited molecules are rapidly quenched by collisions with N and O atoms (Schofield 1979;Slovetsky 1980).…”