Hyperfine Structure of Thallium Chloride

The radio‐frequency spectra of TlCl at very weak electric and magnetic fields have been measured with a molecular beam electric resonance spectrometer. From these spectra the hyperfine interaction constants for the four isotopic species of the molecule were calculated. The constants for 205Tl35Cl in the J = 2,υ = 0J=2,υ=0 state are: eqQ = − 15793.32(50)kHz,cCl = 1.38(10)kHz,cTl = 76.35(10)kHz,c3 = − 0.13(10)kHz,c4 = − 1.54(10)kHz.eqQ=−15793.32(50)kHz,cCl=1.38(10)kHz,cTl=76.35(10)kHz,c3=−0.13(10)kHz,c4=−1.54(10)kHz. A test was made for the polarization of the chlorine nucleus in the electric field of the molecule by comparing the ratio of the quadrupole interaction constants for 205Tl35Cl and 205Tl37Cl to the ratio of the quadrupole interaction constants for the free chlorine atoms. The agreement of the two ratios is within their uncertainties, thus providing no evidence for a polarization effect. In addition, the dependence of the spin–rotation and spin–spin interaction constants on isotope was found to show good agreement with theory.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/69724/2/JCPSA6-50-5-2086-1.pd