Field-induced intensity and Stark shift measurements of the electric dipole moment of ICl in the B 3Π0+ state.

The laser-induced fluorescence spectrum in ICl of the (2’–0‘) vibrational band in the B 3Π0+–X 1Σ+ electronic system has been measured as a function of the electric field strength up to 32.5 kV/cm. Field-induced intensity measurements on I35Cl have been used to determine the magnitude and sign of the electric dipole moment μB in the B state relative to the magnitude and sign of the moment μX 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 state, it was found that μB/μX=+(0.888±0.051). The positive sign indicates that the polarity is the same in the B and the X states. Intensity ratio measurements for Q(0) to R(5) and for Q(1) to R(5) yield similar (but less precise) results. In order to test this first application of the method to excited electronic states, Stark shift measurements were carried out on a number of P-branch Stark components. It was found for I35Cl that |μB/μX|=(0.8984±0.0036), in good agreement with the intensity measurements. The corresponding determination for I37Cl is that |μB/μX|=(0.900±0.014). The present results are in agreement with those obtained earlier from studies of the absorption spectrum by Watanabe et al. [Jpn. J. Appl. Phys. 31, 901 (1992)]. [ABSTRACT FROM AUTHOR]