OPTICAL-EXCITATION OF CO+-N-2

The electrostatic complex of Co+ with a single N-2 molecule is studied by optical excitation of the metal ion. Vibrational structures of suc h electronic transitions show excited state progressions of the comple x modes. A single far-red transition shows little geometry change upon excitation and displays the rotational contour of a nonlinear complex . Yellow transitions show vibrational structure indicative of a gross geometry change with progressions in both stretching and rocking modes . This suggests that CoN2+ possesses a ''T''-shaped ground state and b oth linear and nonlinear excited states. A particular linear upper sta te, the (B) over tilde state, is characterized vibrationally with a ty pical metal-ligand stretching frequency (140 cm(-1)) but a rather flac cid rocking frequency (14 cm(-1)). The geometry change upon 3d(7)4s <- - 3d(8) excitation of the Co+ ion in this complex is discussed in term s of a simple model potential which includes both electrostatic and in ductive components.