A recent paper from our group, in collaboration with Luciano Costa’s group at Fluminense Federal University (Brazil) and Burcu Gurkan’s group at Case Western Reserve University, has been featured by the Joint Center for Energy Storage Research (JCESR).
In this paper, our team used Raman spectroscopy and molecular dynamics (MD) simulations to study the structural and dynamical changes in the solvation shell surrounding Li+ in a ternary electrolyte is composed of a mixture of two ionic liquids (ILs), n-methyl-n-propylpyrrolidinium bis(trifluoromethanesulfonyl)imide ([PYR13][TFSI]) and 1-ethyl-3-methylimidazolium dicyanamide ([EMIM][DCA]), and a lithium bis(trifluoromethanesulfonyl)imide ([Li][TFSI]) salt (0–1 M). The local structure of Li+ in this eutectic was found to be heterogeneous and preferentially solvated by [DCA]. The Raman and MD analyses suggest a wide distribution of solvation. The computations showed increased ion pair lifetime for Li+ –[DCA] and decreased lifetimes for Li+–[TFSI] in the ternary mixture with the increase in the [Li][TFSI] concentration. These results show that the solvation and transport properties of charge carriers in ILs can be modified via the presence of multiple ions with varying degree of coordination, which provides an approach to impact the performance in electrochemical processes.
Garett Tow’s paper on simulating the orthorhombic phase of ammonium perchlorate has been published (Garrett M. Tow and Edward J. Maginn, “Evaluating physical properties of the orthorhombic crystal phase of ammonium perchlorate using a class II force field”, Journal of Chemical Physics, 2018, 149, 244502.
In this paper, we show how a class II force field can adequately capture the structural, thermodynamic and spectroscopic properties of ammonium perchlorate.
Ryan Mullen’s paper on using reaction ensemble Monte Carlo to compute absorption isotherms for CO2 in reactive ionic liquids has appeared in the Journal of Chemical Theory and Computation. In this paper, we show that one can get quantitative agreement with experiment for the absorption of CO2 into an aprotic heterocyclic anion ionic liquid using reaction ensemble Monte Carlo (RxMC) with the semigrand reaction move. Heats of absorption and reaction from both experiment and simulation are exothermic and of comparable magnitude. Replacing experimental Henry’s constants with their simulated counterparts improves the accuracy of a Langmuir-type model at moderate pressures. Nonidealities that affect chemical equilibrium are identified and calculated with high precision.
Our paper entitled “A Molecular Dynamics Investigation Of Actinyl-Ligand Speciation In Aqueous Solution” ( , the dynamics of actinyl–ligand contact ion pair (CIP) dissociation were characterized by calculating rate constants from transition state theory. The transmission coefficient, a dynamical correction factor used to correct for reaction barrier recrossing, was calculated for each actinyl–ligand CIP dissociation event.
The long-awaited paper describing Cassandra and its features has finally been published (Journal of Computational Chemistry, 2017, 38, 1727-1739).The different features and algorithms used in Cassandra are described, along with implementation details and theoretical underpinnings to various methods used. Benchmark and example calculations are shown, and information on how users can obtain the package and contribute to it are provided. We also made the cover! Please cite this paper if you use Cassandra.