Relativistic ab-initio calculations on PdH and PdD:: The rovibronic spectra and rotational splittings

An ab initio theoretical analysis of the rovibronic spectra of the PdH molecule and its heavier isotope PdD is presented. Potential curves of the lowest Lambda S state multiplet (2) Sigma(+), (2) Delta, and (2) Pi are generated in consideration of kinematic relativistic effects in a one-component formalism. We determine the effects of the rotational motion of the nuclei on the vibronic spectra by evaluating matrix elements of a rotational Hamiltonian in the basis of uncoupled vibronic Born-Oppenheimer functions, including the effects of spin-orbit coupling and compare our results to experiment. Moreover, we present predictions for experimentally yet unknown transitions by calculating energy levels, Omega-, and vibrational splittings of-several excited states. (C) 1998 American Institute of Physics. [S0021-9606(98)02709-3].