ELECTRONIC-STRUCTURE OF THE BF2 RADICAL DETERMINED BY AB-INITIO CALCULATIONS AND RESONANCE-ENHANCED MULTIPHOTON IONIZATION SPECTROSCOPY

We report the first electronic absorption spectrum of the baron difluo ride radical. This spectrum appeared in mass-selected multiphoton ioni zation spectra between 235 and 420 nm. Strong bent-linear structure ch anges prevented observations of electronic origin bands. EOM-CCSD ab i nitio calculations suggest that the observed vibrational bands arise f rom (A) over tilde(2)B(1)<--(X) over tilde(2)A(1) (T-vert = 35 100 cm( -1)) one-photon absorption and from (B) over tilde(2)A(1) (3S) <--<-- (X) over tilde(2)A(1) (T-vert = 59 100 cm(-1)) and (C) over tilde (3p) <--<-- (X) over tilde(2)A(1) (T-vert = 63 100 cm(-1)) two-photon tran sitions. Ab initio calculations predicted the geometries and vibration al frequencies of the ground states of the BF2 radical, cation, and an ion. Ab initio calculations also predicted the vertical transition ene rgies to the excited electronic states from the ground state radical. QCISD(T) calculations estimate ionization potentials for BF2 radicals of IPa = 8.66 eV and IPv = 10.44 eV and adiabatic and vertical electro n detachment energies for BR(2)(-) of EA = 1.14 eV and VDE = 1.64 eV. We estimate these ionization and detachment energies to be reliable to about 0.05 and 0.10 eV, respectively.