Absolute molecular Entropies for flexible molecules

This is a collection of input geometries used in https://doi.org/10.1039/D1SC00621E

The project utilized the freely available crest program, which can be obtained from https://github.com/grimme-lab/crest

Entropy calculations with crest

As written in the manuscript there are only a couple of steps necessary for the calculation of absolute molecular entropies:

1. Find the best minimum energy conformer, e.g. by running crest coord --gfnff and subsequent DFT geometry optimizations using censo (https://github.com/grimme-lab/CENSO)

2. For the minimum conformer calculate frequencies (at DFT level) and from the frequencies calculate S_msRRHO. Frequency scaling factors and the rigid-rotor/harmonic oscillator interpolation parameter τ have to be adjusted in the respective programs, e.g. thermo. crest provides a standalone thermo implementation with a default τ = 25.0 cm^-1 and adjustable frequency scaling factors, but at the time of writing is only able to read frequencies in xtb's and Turbomoles vibspectrum format. The respective command is: crest --thermo coord [optional: --fscal <scaling-factor>, --sthr <τ>] which requires a vibspectrum file to be present.

3. Calculate S_conf with crest. We strongly recommend GFN-FF as default due to the high computational cost: crest coord --entropy --gfnff

4. Calculate S_abs = S_msRRHO + S_conf