Accurate First Principles Model Potentials for Intermolecular Interactions

Abstract

The general effective fragment potential (EFP) method provides model potentials for any molecule that is derived from first principles, with no empirically fitted parameters. The EFP method has been interfaced with most currently used ab initio single-reference and multireference quantum mechanics (QM) methods, ranging from Hartree-Fock and coupled cluster theory to multireference perturbation theory. The most recent innovations in the EFP model have been to make the computationally expensive charge transfer term much more efficient and to interface the general EFP dispersion and exchange repulsion interactions with QM methods. Following a summary of the method and its implementation in generally available computer programs, these most recent new developments are discussed.

Analytic second derivative of the energy for density functional theory based on the three-body fragment molecular orbital method

“…[18][19][20][21] The linearscaling QM algorithms [22][23][24][25] have primarily been developed for energy and gradient evaluations; the efficiency of Hessian computations has also been improved. [26][27][28] Some fragment based approaches [29][30][31][32][33][34][35][36][37][38][39][40] feature analytic second derivatives. [41][42][43][44][45][46] The fragment molecular orbital (FMO) method [47][48][49][50][51] is a fragment-based approach.…”

Theoretical estimation of pnicogen bonds and hydrogen bonds in small heterocyclic complexes: Red-shifts and blue-shifts ruled by polarization effects

“…Throughout this study, one particular attention has been focused on the structural alterations and vibration mode shifts in PH 3 , PH 2 F, and PH 2 Cl. Thus, it is expected that the QTAIM topological parameters will corroborate these findings ∆υ str = 17936.4∆ρ -1.322 , R 2 = 0.993 (2) As can be seen, an increase in the electronic density leads to stronger bonds in which the blueshift effects are manifested. In contrast, the red shifts are associated with reductions in the electronic density.…”

“…The appropriate choice of the computational level to be used in theoretical calculations of intermolecular systems, mainly those which are weakly bound, is a theme widely discussed among the theoreticians [2,[54][55]. It is well known that the many-body perturbation theory and density functionals are among the most commonly used theoretical approaches in studies on electronic structure, but it remains inconclusive whether B3LYP or MP2 is the most suitable for use in research on intermolecular systems [48,43,[56][57].…”

CO2Adsorption in Fe2(dobdc): A Classical Force Field Parameterized from Quantum Mechanical Calculations

“…This approach yielded parameters that accurately predicted CO 2 and N 2 adsorption in closed-shell MOFs. Møller−Plesset second-order perturbation theory (MP2) 16 was used to compute interaction energies for Mg 2 (dobdc) and Zn 2 (dobdc) respectively cluster models with CO 2 . Cluster models were designed to describe CO 2 interactions with every atom type present in these MOFs.…”