THE 3D8NI(3F)3D10CU-SIGMA-2-SIGMA-ASTERISK-1 MANIFOLD OF EXCITED ELECTRONIC STATES OF NICU

Diatomic NiCu has been supersonically cooled in a molecular beam and investigated by resonant two-photon ionization spectroscopy. A total of nine band systems connecting the ground 3d(Ni)(9)3d(Cu)10sigma2, X2DELTA5/2 state to the 3d(Ni)8(3F)3d(Cu)10sigma2sigma*1 manifold of states have been found, and bands of eight of these systems have been rotationally resolved and analyzed. L- and S-uncoupling interactions have been found between two pairs of states, resulting in B[11.9]2.5 approximately C[11.9]1.5 and [10.4]2.5 approximately [10.4]1.5(?) heterogeneous perturbations. In the case of the B approximately C interaction, the magnitude of the perturbation matrix element has been deduced. The detailed spectroscopic analysis of the 3d(Ni)8(3F)3d(Cu)10sigma2sigma*1 manifold of states presented in this paper allows the electronic structure of NiCu to be understood in depth and provides a database for comparison to the ligand-field plus spin-orbit calculation of the NiCu excited states presented in the following paper.