Issue 23, 2021

Using computational chemistry to design pump–probe schemes for measuring nitrobenzene radical cation dynamics

Abstract

The electronic potential energy surfaces of the nitrobenzene cation obtained from time-dependent density functional theory and coupled cluster calculations are used to predict the most efficient excitation wavelength for femtosecond time-resolved mass spectrometry measurements. Both levels of theory identify a strongly-coupled transition from the ground state of the nitrobenzene cation with a geometry-dependent oscillator strength, reaching a maximum at 90° C–C–N–O dihedral angle with a corresponding energy gap of ∼2 eV. These results are consistent with the experimental observation in the nitrobenzene cation of a coherent superposition of vibrational states: a vibrational wave packet. Time-resolved measurements using a probe wavelength of 650 nm, nearly resonant with the strong transition, result in enhanced ion yield oscillation amplitudes as compared to excitation with the nonresonant 800 nm wavelength. Analogous behavior is found for the closely related molecules 2- and 4-nitrotoluene. These results demonstrate that computational chemistry can predict the best choice of probe wavelength in time-resolved measurements of vibrational coherent states in molecular cations.

Graphical abstract: Using computational chemistry to design pump–probe schemes for measuring nitrobenzene radical cation dynamics

Supplementary files

Article information

Article type
Paper
Submitted
25 Jan 2021
Accepted
30 May 2021
First published
31 May 2021
This article is Open Access
Creative Commons BY-NC license

Phys. Chem. Chem. Phys., 2021,23, 13338-13348

Using computational chemistry to design pump–probe schemes for measuring nitrobenzene radical cation dynamics

H. A. López Peña, D. Ampadu Boateng, S. L. McPherson and K. M. Tibbetts, Phys. Chem. Chem. Phys., 2021, 23, 13338 DOI: 10.1039/D1CP00360G

This article is licensed under a Creative Commons Attribution-NonCommercial 3.0 Unported Licence. You can use material from this article in other publications, without requesting further permission from the RSC, provided that the correct acknowledgement is given and it is not used for commercial purposes.

To request permission to reproduce material from this article in a commercial publication, 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 commercial 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