Knowledge Bank

Molecular beam electric resonance spectra of several isotopes of the weakly bound complex $N2-HCl$ have been obtained in the $J=1\to O$ and $J=2\to 1$ 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 $\mathrm{<mrow\; data-mjx-texclass="ORD">14</mrow>}N$ and $\mathrm{<mrow\; data-mjx-texclass="ORD">35,37</mrow>}Cl$ 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 $N2-HCl$ studied. The equilibrium hydrogen bond length is $2.42\backslash AA$. The degree of charge distortion is obtained from the observed difference in the $eqQaN$ for the two isomers of $\mathrm{<mrow\; data-mjx-texclass="ORD">15,14</mrow>}N2-H35Cl,14N=15N-H35Cl$ and $\mathrm{<mrow\; data-mjx-texclass="ORD">15</mrow>}N=\mathrm{<mrow\; data-mjx-texclass="ORD">14</mrow>}N-H35Cl$. 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 $eqQaCl$ and the $eqQaD$ 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 $N2-HCl$ along with related weakly bound molecules will be made.