Issue 19, 2020

Ionization energies in solution with the QM:QM approach

Abstract

We discuss a fragment-based QM:QM scheme as a practical way to access the energetics of vertical electronic processes in the condensed phase. In the QM:QM scheme, we decompose the large molecular system into small fragments, which interact solely electrostatically. The energies of the fragments are calculated in a self-consistent field generated by the other fragments and the total energy of the system is calculated as a sum of the fragment energies. We show on two test cases (cytosine and a sodium cation) that the method allows one to accurately simulate the shift of vertical ionization energies (VIE) while going from the gas phase to the bulk. For both examples, the predicted solvent shifts and peak widths estimated at the DFT level agree well with the experimental observations. We argue that the QM:QM approach is more suitable than either an electrostatic embedding based QM/MM approach, a full quantum description at the DFT level with a generally used functional or a combination of both. We also discuss the potential scope of the applicability for other electronic processes such as Auger decay.

Graphical abstract: Ionization energies in solution with the QM:QM approach

Supplementary files

Article information

Article type
Paper
Submitted
13 Nov. 2019
Accepted
22 Janv. 2020
First published
22 Janv. 2020

Phys. Chem. Chem. Phys., 2020,22, 10550-10560

Ionization energies in solution with the QM:QM approach

Z. Tóth, J. Kubečka, E. Muchová and P. Slavíček, Phys. Chem. Chem. Phys., 2020, 22, 10550 DOI: 10.1039/C9CP06154A

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