Liquid-State Structure via Very High-Field Nuclear Magnetic Resonance Discriminates among Force Fields.

Deuterium nuclear magnetic resonance (H-2 NMR) spectra of labeled molecular liquids obtained at high fields, for example, vertical bar B vertical bar = 22.3 T (950 MHz proton NMR), exhibit resolved quadrupolar splittings that reflect the average orientation of the molecules relative to B. Those residual nuclear spin interactions exhibited by benzene and chloroform provide an experimental determination of the leading tensor component of the pair correlation function for these two molecular liquids. In this way, very high-field H-2 NMR may be used to extract unambiguous information about liquid-state structure. Additionally, replicating the experimentally derived pair correlation function using molecular dynamics simulations provides a critical test of simulation force fields.