THE MICROWAVE SPECTRUM, HYPERFINE CONSTANTS, AND STRUCTURE OF $N_{2}-HCl$. THE RADIO FREQUENCY SPECTRUM OF OC-HCl

Molecular beam electric resonance spectra of several isotopes of the weakly bound complex $N_{2}-HCl$ have been obtained in the $J=1 \rightarrow O$ and $J=2 \rightarrow 1$ rotational transitions. These spectra reveal a linear hydrogen-bound complex with the following spectroscopic constants: $ \begin{array}{lcccc} &^{14}N_{2}-H^{35}Cl & ^{15}N_{2}-H^{35}Cl & OC-H^{35}Cl & OC-D^{35}Cl\\ (B + C)/2\quad (MHz) & 1745.6640(8) & 1679.256(2) &&\\ D_{J}\quad (KHz) & 8.56(9) & 7.76(26)&&\\ eqQ^{Cl}_{a}\quad (MHz) & -48.1820(29) &-48.279(11) &-52.0719(14) &-55.2473(7)\\ eqQ^{D}_{a}\quad (MHz) &-& -&- & - 0.1509(32)\\ (eqQ^{N}_{a} 1 + eqO^{N}_{a}2)/2 (MHz)&-4.5150(36) &- &- &-\\ (eqQ^{N}_{a}1 - eqO^{N}_{a}2)/2 (MHz) & 0.036(77) &- &- &- \\ \mu (D) && 1.2496(1) & 1.51783(6)& 1.56231 (10) \end{array}$ Hyperfine information due to the $^{14}N$ and $^{35, 37}Cl$ electric quadrupole coupling constants is used in the structure determination. The HCl subunit makes an average angle of $26^{\circ}$ with the a-axis of the complex in all isotopes of $N_{2}-HCl$ studied. The equilibrium hydrogen bond length is $2.42 \AA$. The degree of charge distortion is obtained from the observed difference in the $eqQ^{N}_{a}$ for the two isomers of $^{15, 14}N_{2}-H^{35}Cl, ^{14}N = ^{15}N-H^{35}Cl$ and $^{15}N = {^{14}N}-H^{35}Cl$. The electric quadrupole coupling constants of Cl and D in OC=HCl and OC=DCl have been determined along with their dipole moments. In OC-DCl the $eqQ^{Cl}_{a}$ and the $eqQ^{D}_{a}$ are seen to project the same angle that the DCl subunit makes with the a-axis of the complex. A discussion and comparison of OC-HCI and $N_{2}-HCl$ along with related weakly bound molecules will be made