15min:

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

In 2004 we determined from the analysis of the Stark effect in the A² - X^{2 +} (0,0) band of system the magnitude of the permanent electric dipole moment, \vertµ\vert, of CaH to be 2.94(16) D and 2.372(12)D for the X^{2 2} (v=0) and A² (v=0) states,respectively. The numbers in parenthesis are 1 error estimates. Recently, two groups have performed high-level, all-electron, ab initio calculation and predicted µ values of 2.623 D and 2.617 D for the X^{2 +}(v=0) state. Although inside a 2 error estimate, these values are somewhat smaller than the experimentally observed value. In an effort to improve the precision of \vertµ\vert, the Stark effect in the B^{2 +} - X^{2 +} (0,0) band system of CaD has been recorded and analyzed. As expected, the Stark effect is about four times larger in CaD compared to CaH. The analysis gives \vertµ\vert of 2.633(27) D and 2.018(33) D for the X^{2 +}(v=0) and B^{2 +}(v=0) state, respectively. A discussion of the isotopic dependence of µ and experimental systematic errors will be given. The trend in µ for the X^{2 +}, A² and B^{2 +} is modeled using a simple molecular orbital picture.