Erin R. Johnson

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A benchmark for non-covalent interactions in solids (C21) based on the experimental sublimation enthalpies and geometries of 21 molecular crystals is presented. Thermal and zero-point effects are carefully accounted for and reference lattice energies and thermal pressures are provided, which allow dispersion-corrected density functionals to be assessed in a(More)
The approximate CCSD(T)/CBS binding energies for the set of 23 hydrogen-bonded dimers (HB23) of the S66 set reported by Řezáč et al. (J. Chem. Theory Comput. 2011, 7, 2427-2438) were expected to be under-estimated based on the known under-binding tendency of the counterpoise correction combined with small basis sets. In this work, we present binding(More)
The difficulty of approximate density functionals in describing the energetics of Diels-Alder reactions and dimerization of aluminum complexes is analyzed. Both of these reaction classes involve formation of cyclic or bicyclic products, which are found to be underbound by the majority of functionals considered. We present a consistent view of these results(More)
The reduced modified Ostrovsky equation is a reduction of the modified Korteweg-de Vries equation, in which the usual linear dispersive term with a third-order derivative is replaced by a linear non-local integral term, representing the effect of background rotation. Here we study the case when the cubic nonlinear term has the same polarity as the rotation(More)
Electrides are a unique class of ionic solids in which the anions are stoichiometrically replaced by electrons localised within the crystal voids. There are only nine electrides with known crystal structures and their study represents a challenge for theory. A systematic investigation of their electronic structure is conducted using semilocal(More)
Large amplitude internal waves are commonly observed in the coastal ocean. In the weakly nonlinear long wave régime, they are often modeled by the Korteweg-de Vries equation, which predicts that the long-time outcome of generic localised initial conditions is a train of internal solitary waves. However, when the effect of background rotation is taken into(More)
It is known that the exact density functional must give ground-state energies that are piecewise linear as a function of electron number. In this work we prove that this is also true for the lowest-energy excited states of different spin or spatial symmetry. This has three important consequences for chemical applications: the ground state of a molecule must(More)
Meta-generalized-gradient approximations (meta-GGAs) in density-functional theory are exchange-correlation functionals whose integrands depend on local density, density gradient, and also the kinetic-energy density. It has been pointed out by Johnson et al. [Chem. Phys. Lett. 394, 334 (2004)] that meta-GGA potential energy curves in dispersion-bound(More)
Electronic excitation and dynamics, charge-transfer in complex environments, optical properties of chromophores in the condensed phase Implementation of CIS and TDDFT into existing GPU accelerated quantum chemistry code, interfacing QM and MM methods. Applications to studies of photophysics in fluorescent proteins, solvation 2009 Doctoral advisor: Xiaosong(More)