Detection of DCl by multiphoton ionization and determination of DCl and HCl internal state distributions

A study of the 2 + 1 resonantly enhanced multiphoton ionization (REMPI) spectrum of DCl is reported. Transition energies for excitation of the F-1 Delta-X(1) Sigma(+) (0,0) and (1,0) bands, as well as the V-1 Sigma(+)-X(1) Sigma(+)(upsilon',0) bands, for upsilon' = 15-19, are presented. The derived molecular constants for the F-X (0,0) and the V-X bands agree well with those previously obtained from analysis of the one-photon VUV absorption spectrum [A. E. Douglas and F. R. Greening, Can. J. Phys. 57, 1650 (1979)]. The ion signals for excitation through various rotational lines in the E-X (0,0) and F-X (0,0) and (1,0) bands are compared with theoretical two-photon line strengths. Extensive power- and J'-dependent ion fragmentation is observed for the former band. No fragmentation is observed in the F-X bands; however, the ion signal strengths are found to vary strongly with J'. This variation of REMPI signal strengths vs J' was shown to be due to an indirect predissociation, as in HCl. Tables of experimental line strength factors for the F-X (0,0) and (1,0) bands of HCl and DCl are reported. Finally, the relative REMPI detection sensitivities for HCl and DCl, through their respective F-X (0,0) R(1) Lines, are compared. (C) 1996 American Institute of Physics.