Molecular Zeeman Effect of Trimethylene Oxide and Trimethylene Sulfide

Abstract

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: gaa = − 0.0073 ± 0.0005, gbb = − 0.0429 ± 0.0007, and gcc = − 0.0747 ± 0.0005; 2χaa − χbb − χcc = − 20.1 ± 0.5 and − χaa + 2χbb − χcc = − 13.5 ± 0.8; Qaa = − 4.9 ± 0.5, Qbb = + 2.3 ± 0.7, and Qcc = + 2.6 ± 1.0. A reliable value of the average magnetic susceptibility in ethylene oxide is also given. The results for trimethylene sulfide are: gaa = − 0.0148 ± 0.0010, gbb = − 0.0169 ± 0.0006, gcc = − 0.0554 ± 0.0005; 2χaa − χbb − χcc = − 20.9 ± 1.0 and − χaa + 2χbb − χcc = − 24.6 ± 1.0; Qaa = − 2.7 ± 1.0, Qbb = + 3.2 ± 1.0, and Qcc = − 0.5 ± 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.