Potential energy surfaces of LaH+and LaH+2

Kalyan K. Das, K. Balasubramanian
1991 Journal of Chemical Physics  
Using the complete active space multiconfiguration self-consistent field (CAS-MCSCF) followed by full second-order configuration interaction (SOCI) calculations, 16 electronic states of LaH + and 8 electronic states of LaH,+ are investigated. The potential energy surface of these electronic states of LaH: and LaH + are computed. These calculations show that the 'F( 5d ' ) ground state of La + ion forms a weak complex with H, . The La + ( 'D) excited state inserts into H, with a small barrier (
more » ... a small barrier ( < 8 kcal/mol) to form the 'A, ground state of LaHc (r, = 2.057 A, 19, = 106"). At the SOCI level of theory LaH,+ is found to be 11 kcal/mol more stable than La + ( 3r;? + H, . Our calculations explain the experimental observations on La+ +H, 4 LaH + + H reaction. The adiabatic ionization potential (IP) of LaH, and LaH are calculated as 5.23 and 5.33 eV, respectively. The ground state of LaH + was found to be a *A state. We compute D, (LaH + > and De (HLa-H + ) as 2.54 eV in excellent agreement with the experimental D, ( LaH + ) = 2.57 eV measured by Armentrout and co-workers. The spinorbit effects of LaH + were also studied using the relativistic configuration interaction (RCI) method. 3722
doi:10.1063/1.459743 fatcat:i3dbpt5xj5fn3pnfem66yiafnu