THE (1)(3)PHI-]A(3)DELTA AND (2)(3)DELTA-]A(3)DELTA (0-0)-TRANSITIONSOF SCANDIUM MONOCHLORIDE

The results of a study of the (1)(3) Phi --> alpha a(3) Delta and (2)( 3) Delta --> alpha(3) Delta near-infrared systems of scandium monochlo ride are presented. The principal subbands of the (0-0) transitions ha ve been observed in the molecular emission spectrum at 1500 K. The ana lysis of the dense rotational structures has been facilitated by the i nformation obtained in laser-induced fluorescence experiments. Indeed, a number of fluorescent lines have been observed, corresponding to De lta Sigma = 0 transitions from (2)(3) Delta(3,2,1)(upsilon = 0) to alp ha(3) Delta(3,2,1)(upsilon = 0) levels, induced after excitation by ne ar-infrared lines of a titanium sapphire laser. The spectra have all b een recorded with a Fourier transform spectrometer. Each substate has been treated as a separate singlet state. The origins of the subbands and rotational constants of the substates are determined, except for ( 2)(3) Delta(1)(upsilon = 0), in which perturbational effects are recog nized. All three states are regular and an estimation of the spin-orbi t constant in the alpha(3) Delta state is made. The wavenumbers of the 900 observed lines are listed in an Appendix. (C) 1995 Academic Press , Inc.