Condensed matter physics is the study of materials in the condensed phase and their properties. Of particular interest is the interrelationship between molecular and bulk properties. In other words, what molecular properties (e.g. bonding) give rise to specific bulk properties (e.g. material strength)? An understanding at the molecular level allows for the development of new materials which can better serve specific technological needs.

At New Mexico State, Faculty researchers and their collaborators are working on various aspects of condensed matter; from nanotubes to molecular liquids employing both experimental and theoretical tools and methodologies.

For example, collaborative work between John Turner and Sylvia McLain of the Department of Chemistry at the University of Tennessee, Chris Benmore and Joan Swienie of Argonne National Labs, and Jacob Urquidi of New Mexico State University, has lead to an investigation of the hydrogen bonding in liquid anhydrous hydrogen fluoride (HF). This liquid, comprised of diatomic molecules, has the strongest hydrogen bonds of any simple molecular fluid. Despite this, the theoretical intermolecular interactions which comprise the liquid structure have been hotly debated for over two decades. It is hoped that this experimental work will help settle some outstanding questions.

Figure 1 shows Reverse Monte Carlo (RMC) Modeling snapshot of 6000 HF molecules. The RMC simulation produces a molecular level model which is consistent with the experimental measurement. The same RMC Model is shown in figure 2 but with the molecules removed. The complexity of the intermolecular hydrogen bonding is clearly demonstrated.

Jacob Urquidi of New Mexico State University together with his collaborator, Jeffery Pottof of Wayne State University, are developing an improved intermolecular force field for acetic acid. To accomplish this, structural information is needed at elevated temperatures and pressures. Of particular interest is the amount of hydrogen bonding occurring via the carbonyl functionality compared to that which occurs via the hydroxyl oxygen. Our preliminary work has shown that neutron diffraction, combined with the method of first order isotope differences, is an effective means for gathering this information