Microwave Spectra and Molecular Constants of Arsine and Stibine

Millimeter and submillimeter wave rotational transitions have been measured for different isotopic species of arsine and stibine from which accurate values of the rotational constants, including centrifugal stretching constants, nuclear quadruple and nuclear magnetic coupling constants, were obtained. Results (in Mc/sec) are for ${}_{}{}^{75}{}_{}{}^{}\mathrm{As}$ ${\mathrm{H}}_3$, $B_0=112\mathrm{} 470.59\pm 0.03$, $D_J=2.925\mathrm{}\pm 0.003$, $D_{\mathrm{JK}}=-3.718\mathrm{}\pm 0.004$, $eqQ=-162.63\mathrm{}\pm 0.03$, $C_N=0.106\mathrm{}\pm 0.003$, $C_K=0.028\mathrm{}\pm 0.014$; for ${}_{}{}^{75}{}_{}{}^{}\mathrm{As}$ ${\mathrm{D}}_3$, $B_0=57\mathrm{} 477.60\pm 0.02$, $D_J=0.741\mathrm{}\pm 0.002$, $D_{\mathrm{JK}}=-0.928\mathrm{}\pm 0.003$, $eqQ=-164.75\mathrm{}\pm 0.03$, $C_N=0.051\mathrm{}\pm 0.003$, $C_K=0.069\mathrm{}\pm 0.015$; for ${}_{}{}^{121}{}_{}{}^{}\mathrm{Sb}$ ${\mathrm{H}}_3$, $B_0=88\mathrm{} 038.99\pm 0.03$, $D_J=1.884\mathrm{}\pm 0.004$, $D_{\mathrm{JK}}=-2.394\mathrm{}\pm 0.015$, $eqQ=460.31\mathrm{}\pm 0.10$, $C_N=0.245\mathrm{}\pm 0.006$, $C_K=0.247\mathrm{}\pm 0.030$; for ${}_{}{}^{123}{}_{}{}^{}\mathrm{Sb}$ ${\mathrm{H}}_3$, $B_0=88\mathrm{} 022.51\pm 0.03$, $D_J=1.884\mathrm{}\pm 0.004$, $D_{\mathrm{JK}}=-2.365\mathrm{}\pm 0.015$, $eqQ=586.65\mathrm{}\pm 0.11$, $C_N=0.130\mathrm{}\pm 0.005$, $C_K=0.165\mathrm{}\pm 0.030$; for ${}_{}{}^{121}{}_{}{}^{}\mathrm{Sb}$ ${\mathrm{D}}_3$, $B_0=44\mathrm{} 694.92\pm 0.03$, $D_J=0.473\mathrm{}\pm 0.004$, $D_{\mathrm{JK}}=-0.598\mathrm{}\pm 0.009$, $eqQ=465.32\mathrm{}\pm 0.10$, $C_N=0.127\mathrm{}\pm 0.006$, $C_K=0.162\mathrm{}\pm 0.030$; for ${}_{}{}^{123}{}_{}{}^{}\mathrm{Sb}$ ${\mathrm{D}}_3$, $B_0=44\mathrm{} 678.81\pm 0.03$, $D_J=0.476\mathrm{}\pm 0.004$, $D_{\mathrm{JK}}=-0.589\mathrm{}\pm 0.010$, $eqQ=593.06\mathrm{}\pm 0.11$, $C_N=0.063\mathrm{}\pm 0.005$, $C_K=0.044\mathrm{}\pm 0.030$.