We are pleased to announce that the 2023 Q-Chem… Read More

Nuclear quantum effects such as zero-point energy and nuclear density delocalization are important in a variety of applications in chemistry and biology. The nuclear-electronic orbital (NEO) approach is a multicomponent quantum chemistry method capable of capturing significant nuclear quantum effects in a conceptually attractive and computationally efficient manner. By treating key nuclei, usually protons, quantum mechanically, the NEO method incorporates nuclear quantum effects and non-Born… Read More

Molecular property calculations have long been a cornerstone of computational chemistry, providing invaluable insights for experimental work. Among these properties, nuclear magnetic resonance (NMR) shieldings play a crucial role in characterizing chemical environments. Conventionally, these calculations rely on the often tedious derivation and implementation of the analytical form of the energy derivative. On the other hand, the energy derivative can be carried out in a numerical manner. In… Read More

Q-Chem is pleased to announce the release of Q-Chem 6.1. A variety of new features have been added, including force decomposition analysis, improvements to our new geometry optimizer, vibronic circular dichroism (VCD) spectra, decompositions of vibronic spectra, PCM solvent effects for nuclear-electronic orbital (NEO) calculations, RI-CC2-EOM-SF, EA, and IP, and many more!