Molpro is a general purpose quantum chemistry software package with a long development
history. It was originally focused on accurate wavefunction calculations for small molecules …

Advances in the development of quantum chemical methods and progress in multicore
architectures in computer science made the simulation of infrared spectra of isolated …

A method is presented, which allows for the rigorous use of symmetry within the construction
of multidimensional potential energy surfaces (PESs). This approach is based on a crude …

We present a combination of the incremental expansion of potential energy surfaces (PESs),
known as n-mode expansion, with the incremental evaluation of the electronic energy in a …

The positions of grid points for representing a multidimensional potential energy surface
(PES) have a non-negligible impact on its accuracy and the associated computational effort …

Semi-quartic force fields (QFF) rely on a Taylor-expansion of the multi-dimensional Born-
Oppenheimer potential energy surface (PES) and are frequently used within the calculation …

We present a new program implementation of the Gaussian process regression adaptive
density-guided approach [Schmitz et al., J. Chem. Phys. 153, 064105 (2020)] for automatic …

We extend the fragmentation-based double incremental expansion in FALCON coordinates
(DIF) and its linear-scaling analogue [C. König and O. Christiansen, J. Chem. Phys., 2016 …

The vibrational Hamiltonian involves two high dimensional operators, the kinetic energy
operator (KEO), and the potential energy surface (PES). Both must be approximated for …

We present a combination of the recently developed double incremental expansion of
potential energy surfaces with the well-established adaptive density-guided approach to grid …