All-electron spin-orbit configuration interaction study on the valence and low-lying Rydberg electronic states of GeH

Germanium monohydride (GeH), an important radical for the growth of semiconductor germanium film, has received much attention. However, the electronic structure and spectroscopic properties of low-lying excited states of the radical have not been well understood, especially the coupling between different electronic states. In this work, eight Lambda-S valence states and four low-lying Lambda-S Rydberg states correlated to the four lowest dissociation limits of GeH are investigated by employing the multireference configuration interaction method. With the inclusion of spin-orbit coupling effect, there are 24 Omega states generated from 12 Lambda-S states. On the basis of computed potential energy curves of the Lambda-S and Omega states, the spectroscopic parameters of bound states are evaluated, which demonstrate that the first Rydberg state 3(2)Sigma(+) located at 5.12 eV is exactly the B-2 Sigma(+) state tentatively assigned by experiment. With the help of the calculated spin-orbit matrix elements, the predissociation mechanism of A(2)Delta state is investigated, which may interpret the fact that V > 2 vibrational levels of A(2)Delta state are difficult to be detected in experiment. Finally, the transition dipole moments and the radiative lifetimes of several vibrational levels of A(2)Delta and a(4)Sigma(-) states are calculated. (C) 2015 Elsevier Ltd. All rights reserved.