Molecular Zeeman Effect of Trimethylene Oxide and Trimethylene Sulfide

The rotational Zeeman effect has been observed in trimethylene oxide and trimethylene sulfide. The molecular $g$ values, magnetic susceptibility anisotropies, and molecular quadrupole moments were obtained for both molecules. The $a$ and $b$ axes are in the molecular plane and the $a$ axis bisects the COC or CSC angle. The magnetic susceptibility values are given below in units of 10⁻⁶ erg/G²·mole, and the molecular quadrupole moments are in units of 10⁻²⁶ esu·cm². The results for trimethylene oxide are: $g_{\mathrm{aa}}{\text{\hspace{0.17em}=\hspace{0.17em}−\hspace{0.17em}0.0073\hspace{0.17em}±\hspace{0.17em}0.0005, g}}_{\mathrm{bb}}\text{\hspace{0.17em}=\hspace{0.17em}−\hspace{0.17em}0.0429\hspace{0.17em}±\hspace{0.17em}0.0007}$ , and $g_{\mathrm{cc}}{\text{\hspace{0.17em}=\hspace{0.17em}−\hspace{0.17em}0.0747\hspace{0.17em}±\hspace{0.17em}0.0005; 2χ}}_{\mathrm{aa}}{\mathrm{\hspace{0.17em}-\hspace{0.17em}\chi }}_{\mathrm{bb}}{\mathrm{\hspace{0.17em}-\hspace{0.17em}\chi }}_{\mathrm{cc}}\text{\hspace{0.17em}=\hspace{0.17em}−\hspace{0.17em}20.1\hspace{0.17em}±\hspace{0.17em}0.5}$ and ${\mathrm{-\hspace{0.17em}\chi }}_{\mathrm{aa}}{\text{\hspace{0.17em}+\hspace{0.17em}2χ}}_{\mathrm{bb}}{\mathrm{\hspace{0.17em}-\hspace{0.17em}\chi }}_{\mathrm{cc}}{\text{\hspace{0.17em}=\hspace{0.17em}−\hspace{0.17em}13.5\hspace{0.17em}±\hspace{0.17em}0.8; Q}}_{\mathrm{aa}}{\text{\hspace{0.17em}=\hspace{0.17em}−\hspace{0.17em}4.9\hspace{0.17em}±\hspace{0.17em}0.5, Q}}_{\mathrm{bb}}\text{\hspace{0.17em}=\hspace{0.17em}+\hspace{0.17em}2.3\hspace{0.17em}±\hspace{0.17em}0.7}$ , and $Q_{\mathrm{cc}}\text{\hspace{0.17em}=\hspace{0.17em}+\hspace{0.17em}2.6\hspace{0.17em}±\hspace{0.17em}1.0}$ . A reliable value of the average magnetic susceptibility in ethylene oxide is also given. The results for trimethylene sulfide are: $g_{\mathrm{aa}}{\text{\hspace{0.17em}=\hspace{0.17em}−\hspace{0.17em}0.0148\hspace{0.17em}±\hspace{0.17em}0.0010, g}}_{\mathrm{bb}}{\text{\hspace{0.17em}=\hspace{0.17em}−\hspace{0.17em}0.0169\hspace{0.17em}±\hspace{0.17em}0.0006, g}}_{\mathrm{cc}}{\text{\hspace{0.17em}=\hspace{0.17em}−\hspace{0.17em}0.0554\hspace{0.17em}±\hspace{0.17em}0.0005; 2χ}}_{\mathrm{aa}}{\mathrm{\hspace{0.17em}-\hspace{0.17em}\chi }}_{\mathrm{bb}}{\mathrm{\hspace{0.17em}-\hspace{0.17em}\chi }}_{\mathrm{cc}}\text{\hspace{0.17em}=\hspace{0.17em}−\hspace{0.17em}20.9\hspace{0.17em}±\hspace{0.17em}1.0}$ and ${\mathrm{-\hspace{0.17em}\chi }}_{\mathrm{aa}}{\text{\hspace{0.17em}+\hspace{0.17em}2χ}}_{\mathrm{bb}}{\mathrm{\hspace{0.17em}-\hspace{0.17em}\chi }}_{\mathrm{cc}}{\text{\hspace{0.17em}=\hspace{0.17em}−\hspace{0.17em}24.6\hspace{0.17em}±\hspace{0.17em}1.0; Q}}_{\mathrm{aa}}{\text{\hspace{0.17em}=\hspace{0.17em}−\hspace{0.17em}2.7\hspace{0.17em}±\hspace{0.17em}1.0, Q}}_{\mathrm{bb}}\text{\hspace{0.17em}=\hspace{0.17em}+\hspace{0.17em}3.2\hspace{0.17em}±\hspace{0.17em}1.0}$ , and $Q_{\mathrm{cc}}\text{\hspace{0.17em}=\hspace{0.17em}−\hspace{0.17em}0.5\hspace{0.17em}±\hspace{0.17em}1.6}$ . Due to the large vibration–rotation interaction in trimethylene sulfide, it was found that consistent $g$ values could be obtained only when this interaction was included in the analysis. The results are compared with previously measured oxygen‐ and sulfur‐containing molecules.