Table of Contents
Laser Chemistry
Volume 14, Issue 4, Pages 207-216

Rotationally Resolved Rate Constant Measurements for Removal of CH(A2Δ and B2) by Ketene

1Instituto de Química Física “Rocasolano”, C.S.I.C., Serrano 119, Madrid 28006, Spain
2SRI International, 333 Ravenswood Ave., Menlo Park 94025, California, USA

Received 29 May 1993

Copyright © 1994 Hindawi Publishing Corporation. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


Rate constants for total removal of CH(A2Δ) and CH(B2) in collisions with ketene were measured. For the A2Δ state, rate constants increased with vibrational quantum number; measured values were (4.5 ± 0.5) × 10-10 cm3 molec-1 s-1 and (8.0 ± 1) × 10-01 cm3 molec-1 s-1 for v′ = 0 and v′ = 2 respectively. For v′ = 0, rotational levels with quantum numbers from N′ = 4 to N′ = 16 were removed with similar rates within experimental errors; collisional disappearance of levels with higher rotational quantum numbers was faster for a factor of about 1.4. Calculations of cross sections for ketene and other fast colliders, assuming a multipole model, obtained a qualitative correlation with experimental values. CH(B2) was more efficiently removed than CH(A2Δ, v′ = 0); for the lowest rotational levels a rate constant of (5.8 ± 0.3) × 10-10 cm3 molec-1 s-1 was measured and a moderate increase with rotational quantum number was observed.