15min:

TIMOTHY C. STEIMLE AND JINHAI CHEN, Chemistry and Biochemistry, Arizona State University, Tempe, AZ USA 85287.

Sometimes ago the MIT group analyzed the Doppler limited optical Stark Spectrum for the B² _5/2-X² _5/2(1,0) Q(2.5) line of NiH to determine the permanent electric dipole moments, nu, of 2.4\pm0.1 D and 0.3\pm0.1 D for the X² _5/2 and B² _5/2 states, respectively. The ground state value of nu is routinely predicted to assess the quality of electronic structure predictions. In an effort to reduce the uncertainty in the experimental value of nu we have analyzed the optical Stark spectrum of the Q(2.5) and P(3.5) of a molecular beam sample. A molecular beam was generated by skimming the output of a laser ablation/supersonic expansion. The dipole moments were determined to be 2.44\pm0.02 D and 0.36\pm0.02 D for the X² _5/2 and B² _5/2 states, respectively. The observed trends in the nu value for the ground state of the first row transition metal monohydrides will be rationalized.