Knowledge Bank

The magnetic vibrational circular dichroism (MVCD) spectra of the E-symmetry, $\nu 4$ mode of $HCCl3,HCBr3$, and $DCCl3$ are presented. In each case, an MVCD A-term indicating a first order vibrational Zeeman effect is observed. The vibrational g-values for the $\nu 4$ mode of these haloforms were determined for the first time by moment analysis of the MVCD and absorption spectra. The fact that similar MVCD intensity is found for both gas and solution phase $HCCl3$ and $HCBr3$ indicates that there is little contribution from the Coriolis coupling, which is generally the major contributor to the vibrational Zeeman effect. A partially charged ``elastic bar'' model is used to qualitatively explain the observed MVCD A-terms.