Benchmarking the Lithium–Thiophene Complex

Enhancing σ/π-type copper(i)⋯thiophene interactions by metal doping (metal = Li, Na, K, Ca, Sc)

Metal atom doping on thiophene can enhance the Cu⋯thiophene interactions. Enhancement factors are determined by electrostatic potentials of the molecular surface and the electronic configuration of the doping metal.

Non-adiabatic effects in thermochemistry, spectroscopy and kinetics: the general importance of all three Born–Oppenheimer breakdown corrections

Analytical and numerical solutions describing Born–Oppenheimer breakdown in a simple, widely applicable, model depict shortcomings in modern computational methods.

Ab Initio Quantum Mechanical Description of Noncovalent Interactions at Its Limits: Approaching the Experimental Dissociation Energy of the HF Dimer

Hydrogen fluoride dimer is a perfect model system for studying hydrogen bonding. Its size makes it possible to apply the most advanced theoretical methods available, yet it is a full-featured complex of molecules with nontrivial electronic structure and dynamic properties. Moreover, the dissociation energy of the HF dimer has been measured experimentally with an unparalleled accuracy of ±1 cm(-1)(Bohac et al. J. Chem. Phys. 1992, 9, 6681). In this work, we attempt to reproduce it by purely ab initio means, using advanced quantum-mechanical computational methods free of any empiricism. The purpose of this study is to demonstrate the capabilities of today's computational chemistry and to point out its limitations by identifying the contributions that introduce the largest uncertainty into the result. The dissociation energy is calculated using a composite scheme including large basis set CCSD(T) calculations, contributions of higher excitations up to CCSDTQ, relativistic and diagonal Born-Oppenheimer corrections and anharmonic vibrational calculations. The error of the calculated dissociation energy is 0.07 kcal/mol (25 cm(-1), 2.5%) when compared to the experiment. The major part of this error can be attributed to the inaccuracy of the calculations of the zero-point vibrational energy.

Evaluation of composite schemes for CCSDT(Q) calculations of interaction energies of noncovalent complexes

Evaluation of composite schemes for CCSDT(Q) calculations of interaction energies of noncovalent complexes.