FIELD-INDUCED INTENSITY AND STARK SHIFT MEASUREMENTS OF THE ELECTRIC-DIPOLE MOMENT OF ICI IN THE B-(3)PI(0+) STATE

The laser-induced fluorescence spectrum in ICl of the (2'-0'') vibrati onal band in the B (3) Pi(0+)-X (1) Sigma(+) electronic system has bee n measured as a function of the electric field strength up to 32.5 kV/ cm. Field-induced intensity measurements on (ICl)-Cl-35 have been used to determine the magnitude and sign of the electric dipole moment mu( B) in the B state relative to the magnitude and sign of the moment mu( X) in the X state. From the intensity ratio of the field-induced line Q(0) to the allowed Stark component P(1,0), which has the same upper s tate, it was found that mu(B)/mu(X)=+(0.888+/-0.051). The positive sig n indicates that the polarity is the same in the B and the X states. I ntensity ratio measurements for Q(0) to R(5) and for Q(1) to R(5) yiel d similar (but less precise) results. In order to test this first appl ication of the method to excited electronic states, Stark shift measur ements were carried out on a number of P-branch Stark components. It w as found for (ICl)-Cl-35 that \mu(B)/mu(X)\=(0.8984+/-0.0036), in good agreement with the intensity measurements. The corresponding determin ation for (ICl)-Cl-37 is that \mu(B)/mu B\=(0.900+/-0.014). The presen t results are in agreement with those obtained earlier from studies of the absorption spectrum by Watanabe et al. [Jpn. J. Appl. Phys. 31; 9 01 (1992)].