13C relaxation and anisotropic molecular reorientation in liquid dibromomethane

✍ Scribed by Lewis E. Nance; Marty R. Nealey; A. A. Rodriguez

• Publisher: John Wiley and Sons
• Year: 1990
• Tongue: English
• Weight: 474 KB
• Volume: 28
• Category: Article
• ISSN: 0749-1581
• DOI: 10.1002/mrc.1260280104

✦ Synopsis

Abstract

Although dibromomethane is a simple molecule, little work has been directed toward the analysis of its reorien‐tational motion. This is surprising, since two components of its inertia tensor are nearly degenerate and may, in principle, be treated as a quasi‐symmetric top. The ^13^C spin–lattice relaxation times and nuclear Overhauser enhancements were measured at various temperatures in the liquid phase. Field‐dependent measurements indicated the presence of the scalar relaxation mechanism. Calculated rotational diffusion constants were found to be in reasonable agreement with values predicted by the J‐diffusion model of inertially controlled reorientation. The results show that scalar coupling of the second kind is an important mechanism for ^13^C spin–lattice relaxation in this molecule. The data further indicates that dibromomethane may indeed be exhibiting quasi‐symmetric top behavior of this phase.