Molecular Rotational Zeeman Effect in Thioformaldehyde

The high‐field rotational Zeeman effect has been observed in thioformaldehyde. The magnetic susceptibility anisotropies are ${\text{2 χ}}_{\mathrm{aa}}{\mathrm{-\; \chi }}_{\mathrm{bb}}{\mathrm{-\; \chi }}_{\mathrm{cc}}{\text{= 52.3 ± 1.1 (× 10}}^{\text{−6}}\hspace{0.17em}\mathrm{erg}/{\mathrm{G}}^2·\mathrm{mole})$ and ${\text{2 χ}}_{\mathrm{bb}}{\mathrm{-\; \chi }}_{\mathrm{aa}}{\mathrm{-\; \chi }}_{\mathrm{cc}}\text{= −5.1 ± 0.7}$ . The molecular g values with uniquely determined signs are $g_{\mathrm{aa}}{\text{= −5.2602 ± 0.0068,\hspace{0.17em}g}}_{\mathrm{bb}}\text{= −0.1337 ± 0.0004}$ , and $g_{\mathrm{cc}}\text{= −0.0239 ± 0.0004}$ . c is the out‐of‐plane axis and the a axis is the dipole axis. g_aa represents the largest molecular g value yet measured. Use of these five Zeeman parameters and the known structure gives the molecular quadrupole moments: $Q_{\mathrm{aa}}{\text{= 3.0± 0.7 (× 10}}^{\text{−26}}\hspace{0.17em}\mathrm{esu}·{\mathrm{cm}}^2{\mathrm{),\hspace{0.17em}Q}}_{\mathrm{bb}}{\text{= −2.4 ± 0.5,\hspace{0.17em}Q}}_{\mathrm{cc}}\text{= −0.6 ± 1.1}$ ; the diagonal elements of the paramagnetic susceptibility tensor: ${\chi }_{\mathrm{aa}}^p{\text{= 45.8 ± 0.3 (× 10}}^{\text{−6}}\hspace{0.17em}\mathrm{erg}/{\mathrm{G}}^2·\mathrm{mole}{\mathrm{),\hspace{0.17em}\chi }}_{\mathrm{bb}}^p{\text{= 88.3 ± 0.6,\hspace{0.17em}χ}}_{\mathrm{cc}}^p\text{= 82.6 ± 0.6}$ ; and the anisotropies in the second moments of the electronic charge distribution. By estimating the out‐of‐plane second moment of the electronic charge distribution as ${\mathrm{〈\; c}}^2{\text{〉 = 4.6 ± 0.4 (× 10}}^{\text{−16}}\hspace{0.17em}{\mathrm{cm}}^2)$ using free atom values, we have evaluated the remaining individual second moments of the electronic charge distribution to be ${\mathrm{〈\; a}}^2{\text{〉 = 21.1 ± 0.6 (× 10}}^{\text{−16}}\hspace{0.17em}{\mathrm{cm}}^2)$ and ${\mathrm{〈\; b}}^2\text{〉 = 6.6 ± 0.5}$ . The diagonal elements of the diamagnetic and total magnetic susceptibility tensor also follow from the above estimation of ${\mathrm{〈\; c}}^2〉$ and are ${\chi }_{\mathrm{aa}}^d{\text{= −47.5 ± 2.5 (× 10}}^{\text{−6}}\hspace{0.17em}\mathrm{erg}/{\mathrm{G}}^2·\mathrm{mole}{\mathrm{),\hspace{0.17em}\chi }}_{\mathrm{bb}}^d{\text{= −109.1 ± 3.0,\hspace{0.17em}χ}}_{\mathrm{cc}}^d{\text{= −117.6 ± 3.4,\hspace{0.17em}χ}}_{\mathrm{aa}}{\text{= −1.7 ± 2.5,\hspace{0.17em}χ}}_{\mathrm{bb}}\text{= −20.8 ± 3.1}$ , and ${\chi }_{\mathrm{cc}}\text{= −35.0 ± 3.5}$ , giving the bulk magnetic susceptibility as $\mathrm{\chi \; =}\frac{1}{3}{\mathrm{(\chi }}_{\mathrm{aa}}{\mathrm{+\; \chi }}_{\mathrm{bb}}{\mathrm{+\; \chi }}_{\mathrm{cc}}{\text{) = −19.2 ± 1.8 (× 10}}^{\text{−6}}\hspace{0.17em}\mathrm{erg}/{\mathrm{G}}^2·\mathrm{mole}$ . These values are then compared to those of the oxygen analog, formaldehyde, and trends in this pair are compared to several other previously studied oxygen‐sulfur analogs.