Fourier Transform Spectroscopy: Extensive Analysis of the A2II -> X2E+ and B2E+ -> X2E+ Systems of Yttrium Oxide

An extensive rotational analysis of the blue-green and orange electronic systems of the YO molecule has been performed for a number of bands in the Av = 0 sequences of the B 2 + __ + and A 2fl + systems. This is the first example of the study of a molecular emission spectrum recorded in the visible range by means of high-resolution Fourier transform spectroscopy. The yttrium oxide spectrum was excited in a "composite-wall" hollow-cathode discharge tube cooled with liquid nitrogen. With the help of an elaborate method of calculation, a simultaneous multiband fitting is carried out on the (0, 0) and (1, 1) bands of B X and A X systems, while the A X (2, 2), (3, 3), (4, 4), and (5, 5) bands are fitted separately. Small parameters are evaluated in V = 0 and V = 1 levels (such as the spin-splitting parameter in the ground state, A-doubling p and q parameters in the A state), thus allowing a detailed discussion of the model used and the nature of interactions. Equilibrium constants are determined in the X, A, and B states, and in addition Ae, aA, Pe, and a in the A state. Subject headings: laboratory spectra - molecular processes