Radiative lifetimes for the A1Pi and B1Δ states of the CH+ molecule with application to the CH+ abundance in Zeta Ophiuchi

Using an electron-beam phase-shift apparatus, we have measured radiative lifetimes of 270plus-or-minus75 ns and 290plus-or-minus75 ns, respectively, for v'=1 and 2 levels of the A1II state of the CH+ molecule, and lifetimes of 180plus-or-minus50 ns and 165plus-or-minus50 ns for the v'=0 and 1 levels, respectively, of the B1Δ state of CH+. We find relatively poor agreement with lifetimes calculated from the theoretical transition moment of Yoshimine et al. where lifetimes of 840 and 885 ns are predicted for the v = 1 and 2 levels of the A1 II state. Closer, but still unsatisfactory, agreement is found with the lifetimes of 495 +- 50 ns and 530 +- 50 ns found experimentally for ν' = 1 and 2 of the A1 II state by Brzozowski et al. Although this range of values is still undesirably large, and the origin of the discrepancies obscure, an f0-0 of 0.014 +- 0.003 is recommended from the data. This f-value represents a considerable improvement in the reliability of the oscillator strength, and concomitantly in column densities from observations and the radiative recombination rates calculated from theory. (U.S.)