			15min:

FOURIER TRANSFORM EMISSION SPECTROSCOPY OF THE E²

--X²

⁺ TRANSITION OF CaH AND CaD.

R. S. RAM, K. TERESZCHUK AND P. F. BERNATH, Department of Chemistry, University of York, Heslington, York YO10 5DD, UK; I. E. GORDON, Harvard-Smithsonian Center for Astrophysics, Cambridge, MA 02138, USA; K. A. WALKER, Department of Physics, University of Toronto, Toronto, Ont., M5S 1A7, Canada.

The emission spectra of CaH and CaD have been recorded at high resolution using a Fourier transform spectrometer and bands belonging to the E² --X² Sigma ⁺ transition have been measured in the 20100--20700 cm^-1 region. A rotational analysis of 0--0 and 1--1 bands of both the isotopologues has been carried out. The present measurements have been combined with the previously available pure rotation and vibration-rotation data to provide improved spectroscopic constants for the E² state. The constants Delta G_1/2=1199.8810(32) cm^-1, B_e=4.344659(45) cm^-1, alpha _e=0.121869(88) cm^-1, r_e=1.986718 Å for CaH, and Delta G_1/2=868.7438(46) cm^-1, B_e=2.212496(51) cm^-1, alpha _e=0.036509(97) cm^-1, r_e=1.993396(23) Å for CaD have been determined.

An analysis of the corresponding transitions of SrH and SrD in the 18600--19300 cm^-1 region will also be reported.