Volume 211, 2018

Identifying pragmatic quasi-harmonic electronic structure approaches for modeling molecular crystal thermal expansion

Abstract

Quasi-harmonic approaches provide an economical route to modeling the temperature dependence of molecular crystal structures and properties. Several studies have demonstrated good performance of these models, at least for rigid molecules, when using fragment-based approaches with correlated wavefunction techniques. Many others have found success employing dispersion-corrected density functional theory (DFT). Here, a hierarchy of models in which the energies, geometries, and phonons are computed either with correlated methods or DFT are examined to identify which combinations produce useful predictions for properties such as the molar volume, enthalpy, and entropy as a function of temperature. The results demonstrate that refining DFT geometries and phonons with single-point energies based on dispersion-corrected second-order Møller–Plesset perturbation theory can provide clear improvements in the molar volumes and enthalpies compared to those obtained from DFT alone. Predicted entropies, which are governed by vibrational contributions, benefit less clearly from the hybrid schemes. Using these hybrid techniques, the room-temperature thermochemistry of acetaminophen (paracetamol) is predicted to address the discrepancy between two experimental sublimation enthalpy measurements.

Graphical abstract: Identifying pragmatic quasi-harmonic electronic structure approaches for modeling molecular crystal thermal expansion

Associated articles

Supplementary files

Article information

Article type
Paper
Submitted
26 Feb 2018
Accepted
05 Mar 2018
First published
05 Mar 2018

Faraday Discuss., 2018,211, 181-207

Author version available

Identifying pragmatic quasi-harmonic electronic structure approaches for modeling molecular crystal thermal expansion

Jessica L. McKinley and G. J. O. Beran, Faraday Discuss., 2018, 211, 181 DOI: 10.1039/C8FD00048D

To request permission to reproduce material from this article, please go to the Copyright Clearance Center request page.

If you are an author contributing to an RSC publication, you do not need to request permission provided correct acknowledgement is given.

If you are the author of this article, you do not need to request permission to reproduce figures and diagrams provided correct acknowledgement is given. If you want to reproduce the whole article in a third-party publication (excluding your thesis/dissertation for which permission is not required) please go to the Copyright Clearance Center request page.

Read more about how to correctly acknowledge RSC content.

Social activity

Spotlight

Advertisements