Robert Q. Topper

Professor of Chemistry

Aerosolized nanoparticles

This work originally developed from postdoctoral research at the University of Rhode Island which was directed by David Freeman. Nanoparticles of ammonium chlorides, nitrates, sulfates and other salts are formed in the atmosphere as a result of natural and human sources, and our current research focuses on their structures and reactivity trends as a function of size. Our latest work (see (1) below) indicates that ammonium fluoride clusters exhibit three different kinds of hydrogen bonds.

(1) J.J. Biswakarma*, V. Ciocoi* and R.Q. Topper, Energetics, thermodynamics, and hydrogen bond diversity in ammonium halide clusters, Journal of Physical Chemistry A, 120 (40), pp. 7924-7934 (2016). The above link leads to a free download for registered ACS site users; registration is free. This link leads to the article's abstract.

(2) R.Q. Topper, W. V. Feldmann*, I. Markus*, D. Bergin*, and P.R. Sweeney*, Simulated annealing and density functional theory calculations of structural and energetic properties of the ammonium chloride clusters (NH4Cl)n, (NH4+)(NH4Cl)n and (Cl)(NH4Cl)n, n = 1–13, Journal of Physical Chemistry A, 115 (38), pp. 10423-10432 (2011).

 (3) A. Matro, D.L. Freeman, and R.Q. Topper, Computational study of the structures and thermodynamic properties of ammonium chloride clusters using a parallel J-walking approach,Journal of Chemical Physics104, 8690 (1996).

* = Undergraduate student researcher