Multi-state calculations by solution of the complex eigenvalue Schroedinger equation
Recent applications: I .D. Petsalakis, D. Tzeli and G. Theodorakopoulos, Theoretical study on the electronic states of NaLi. J. Chem. Phys. 129, 054306 (2008), I. D. Petsalakis and G. Theodorakopoulos, Theoretical study of nonadiabatic interactions, radiative lifetimes and predissociation lifetimes of excited states of BH. Molecular Physics 105 333 (2007)
Different types of coupling interactions, not accounted for by Born -Oppenheimer calculations exist between the excited electronic states of a molecule, which may lead to spectral perturbation and predissociation phenomena. In TPCI a multi-state complex scaling method is employed for the calculation of spectral perturbations and predissociation resonances, where all the interactions between the different states are included in the same complex eigenvalue Schroedinger equation [1,2]
Excited electronic states of BeH, width of the v=1 B 2Ð state
Molecular electronic states lying above the first ionization limit autoionize. A CCR (complex coordinate rotation) configuration interaction calculation can determine the resonance .
Autoionizing electronic states of HeH, stabilization of the calculated width 
1. I.D.Petsalakis, G.Theodorakopoulos and R.J.Buenker, Theoretical ab initio study of the electronic states of KrH and KrH+..Quantum defect and complex coordinate calculations on the Rydberg states of KrH. J.Chem.Phys. 119 2004 (2003)
2. I.D.Petsalakis, D.Papadopoulos, G.Theodorakopoulos and R.J.Buenker , Theoretical calculations on the linewidths of rovibrational levels of the 3d Rydberg states of BeH and BeD. J.Phys. B. 32, 3225 (1999)
3. M. Honigmann, G. Hirsch, R.J. Buenker, I.D. Petsalakis and G. Theodorakopoulos, Complex coordinate calculations on autoionizing states of HeH and H2, Chem. Phys. Let. 305 465 (1999).