DYE-LASER EXCITATION STUDIES OF THE (A)OVER-TILDE(2)PI(100) (020)-X(2)SIGMA(+)(020)/(000) BANDS OF CAOD - ANALYSIS OF THE (A)OVER-TILDE(2)PI(100)SIMILAR-TO(020) FERMI RESONANCE/

The CaOD (A) over tilde (2) Pi(100)/(020)-(X) over tilde (2) Sigma(+)( 020)/(000) bands have been rotationally analyzed via high resolution l aser excitation. All measured line positions have been included in a g lobal matrix deperturbation that takes account of the Renner-Teller, s pin-orbit, and Fermi resonance interactions occurring in the (A) over tilde(100)(020) (2) Pi vibronic manifold. The corresponding bands of C aOH were studied previously; in the present work, two new CaOH subband s, (A) over tilde(020)kappa (2) Pi-(X) over tilde(020), were recorded, and the complete data set for CaOH has been refitted using the improv ed model reported in this paper. The Fermi resonance parameter for CaO D has been determined as \W-1\ = 5.2707(22) cm(-1) for CaOH, the newly determined value, \W-1\ = 10.3256(5) cm(-1) is very close to that det ermined originally. The (100)similar to(020) Fermi interaction in the (X) over tilde (2) Sigma(+) state has also been investigated for both isotopomers. The vibrational dependence of the Renner-Teller parameter epsilon omega(2) has been characterized, yielding values of the anhar monic quartic parameter, (g) over cap(4) = -0.1002(3) and -0.0666(5) c m(-1) for CaOH and CaOD, respectively. The ''harmonic'' Renner-Teller parameters cm are thus deduced as epsilon omega(2) = -35.6622(19) and -26.5605(31) cm(-1) for CaOH and CaOD, respectively. The equilibrium b ond lengths, molecular force constants and Coriolis coupling constants for both the (A) over tilde and (X) over tilde states have been evalu ated. (C) 1996 American Institute of Physics.