Jump to main content
Jump to site search

Issue 24, 2014
Previous Article Next Article

On the molecular mechanism of non-radiative decay of nitrobenzene and the unforeseen challenges this simple molecule holds for electronic structure theory

Author affiliations

Abstract

In this work, we present a complete mechanistic picture of the non-radiative decay of the mono-substituted aromatic compound nitrobenzene from the bright singlet state to the electronic ground state. This mechanism involves internal conversion (IC) and inter-system crossing (ISC) along three dominating internal coordinates of the nitro group and consistently explains the experimental findings. Relaxation from the lowest triplet state via ISC occurs along the out-of-plane bending coordinate of the nitro group, while initial IC as well as ultrafast ISC into the triplet manifold take place along symmetric NO stretching and ONO bending modes that have not been considered yet. The proposed mechanism is based on high-level single- and multi-reference electronic structure calculations employing ADC3, MOM-CCSD(T), EOM-CCSD, DFT/MRCI and CAS-SCF/NEVPT2 levels of theory, which is, as we will demonstrate, absolutely necessary to assure a reliable and sufficiently accurate theoretical description of nitrobenzene. The need for third-order methods will be traced back to the large double-excitation character of about 50% of the second excited singlet state of nitrobenzene. As a result, second-order methods like approximate coupled-cluster of second order (CC2) and partially even (EOM-)CCSD yield a qualitatively wrong picture of the excited states. Surprisingly, already the description of the ground state geometries is problematic at the CC2 and partially also CCSD level of theory.

Graphical abstract: On the molecular mechanism of non-radiative decay of nitrobenzene and the unforeseen challenges this simple molecule holds for electronic structure theory

Back to tab navigation
Please wait while Download options loads

Supplementary files

Publication details

The article was received on 21 Mar 2014, accepted on 01 May 2014 and first published on 02 May 2014


Article type: Paper
DOI: 10.1039/C4CP01232A
Citation: Phys. Chem. Chem. Phys., 2014,16, 12393-12406
  •   Request permissions

    On the molecular mechanism of non-radiative decay of nitrobenzene and the unforeseen challenges this simple molecule holds for electronic structure theory

    Jan-M. Mewes, V. Jovanović, C. M. Marian and A. Dreuw, Phys. Chem. Chem. Phys., 2014, 16, 12393
    DOI: 10.1039/C4CP01232A

Search articles by author