TY - JOUR
T1 - A beam experiment on excimer formation in collisions of Kr*(3P0), Kr*(3P2), and Xe* atoms with Br-containing molecules
AU - Vredenbregt, E.J.D.
AU - van Besouw, M.P.M.
AU - Vrakking, M.J.J.
AU - Mietus, M.J.
AU - Gerrits, C.E.P.
AU - Beijerinck, H.C.W.
PY - 1993/5/1
Y1 - 1993/5/1
N2 - The reactions of metastable Kr* and Xe* atoms with several Br-containing
molecules are studied with a beam-gas experimental apparatus. For Kr*,
state selection of the metastable atom beam is employed to investigate
the influence of the initial fine-structure state
Kr*(3P0) and Kr*(3P2) on the
reaction. Trial-and-error simulation of the observed emission spectra
results in modified potential energy curves for the X, A(3/2), B, and C
states of the KrBr and XeBr excimer products and corresponding
transition moments. The propensity for conservation of the
Kr+(2P1/2) ion core in the reactions of
Kr*(3P0) is observed to be between 36% and 51%,
depending on the target, while for the
Kr+(2P3/2) core the propensity is close
to 100%. This is in general agreement with the results of Sadeghi,
Cheaib, and Setser [J. Chem. Phys. 90, 219 (1989)] for Ar*. The reactive
cross section is appreciably smaller for Kr*(3P0)
than for Kr*(3P2). For several reagents, the
analysis leads to a preference for formation of KrBr and XeBr in the C
state, different from results of flowing afterglow experiments. This
points to incomplete correction for collisional relaxation and for
overlap of B→X and C→A(3/2) emission in previous work. For
most reagents, the vibrational distributions are analogous for both XeBr
and KrBr in both the C and B states. For XeBr(B), the results are
generally in agreement with the work of Tamagake, Kolts, and Setser [J.
Chem. Phys. 74, 4286 (1981)].
AB - The reactions of metastable Kr* and Xe* atoms with several Br-containing
molecules are studied with a beam-gas experimental apparatus. For Kr*,
state selection of the metastable atom beam is employed to investigate
the influence of the initial fine-structure state
Kr*(3P0) and Kr*(3P2) on the
reaction. Trial-and-error simulation of the observed emission spectra
results in modified potential energy curves for the X, A(3/2), B, and C
states of the KrBr and XeBr excimer products and corresponding
transition moments. The propensity for conservation of the
Kr+(2P1/2) ion core in the reactions of
Kr*(3P0) is observed to be between 36% and 51%,
depending on the target, while for the
Kr+(2P3/2) core the propensity is close
to 100%. This is in general agreement with the results of Sadeghi,
Cheaib, and Setser [J. Chem. Phys. 90, 219 (1989)] for Ar*. The reactive
cross section is appreciably smaller for Kr*(3P0)
than for Kr*(3P2). For several reagents, the
analysis leads to a preference for formation of KrBr and XeBr in the C
state, different from results of flowing afterglow experiments. This
points to incomplete correction for collisional relaxation and for
overlap of B→X and C→A(3/2) emission in previous work. For
most reagents, the vibrational distributions are analogous for both XeBr
and KrBr in both the C and B states. For XeBr(B), the results are
generally in agreement with the work of Tamagake, Kolts, and Setser [J.
Chem. Phys. 74, 4286 (1981)].
U2 - 10.1063/1.464546
DO - 10.1063/1.464546
M3 - Article
SN - 0021-9606
VL - 98
SP - 7903
EP - 7925
JO - Journal of Chemical Physics
JF - Journal of Chemical Physics
IS - 10
ER -