FO+ AND FO AB-INITIO VIBRATIONAL-CONSTANTS

The potential energy surfaces for both FO neutral and cation were calculated at CCSD(T)/cc-pVTZ (sixty basis functions). From these surfaces the vibrational levels were obtained using the Fourier grid Hamiltonian method. The spectroscopic constants obtained are: FO omega(e)=1072 cm(-1) and omega(e)x(e)=12 cm(-1), FO+ omega(e)=1331 cm(-1) and omega(e)x(e)=11 cm(-1). The same calculations on the isoelectronic (to FO+) O-2 molecule yield an omega(e) within 1% of the spectroscopically determined value and within 20% for omega(e)x(e). The Franck-Condon factors were calculated for transitions from the lowest two levels of FO to FO+. The peak intensity for the transition FO+(X(3) Sigma(-))<--FO(X(2) Pi upsilon'=0) occurs at upsilon'=2.