Experimental determination of the electric dipole moment in the AΠ2and BΣ+2states of CaCl

Abstract

The first experimental determination of excited-state dipole moments of an alkaline-earth monohalide radical is reported. Rotational transitions in the A ${\mathrm{}}^2$Π-X ${\mathrm{}}^2$ ${\Sigma }^{+}$ and B ${\mathrm{}}^2$ ${\Sigma }^{+}$-X ${\mathrm{}}^2$ ${\Sigma }^{+}$band systems of CaCl were studied in an external electric field. With the application of laser spectroscopy to a molecular beam the Stark shifts and splittings of individual lines were precisely measured. As the electric dipole moment of the ground state was known from previous investigations the excited-state dipole moments could be determined as μ(A ${\mathrm{}}^2$Π)=3.54(10) D and μ(B ${\mathrm{}}^2$ ${\Sigma }^{+}$)=4.026(60) D, the absolute error of the measurements given in parentheses.