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Title: Calculations of the relative energies of the low-lying electronic states of 2,7-naphthoquinodimethane and 2,7-naphthoquinone. Substitution of oxygen for CH 2 is predicted to increase the singlet-triplet energy difference ( ΔE ST )

Abstract

CASSCF and CASPT2 calculations have been performed on the triplet and two lowest-lying singlet states of the 2,7-naphthoquinodimethane (NQDM) and 2,7-naphthoquinone (NQ) diradicals. Both diradicals are predicted to have triplet ground states but to differ in the ordering of the two lowest singlet states, with E(1A1) < E(1B2) in NQDM, but E(1A1) > E(1B2) in NQ. The reason for the difference in ordering of the singlet states in these two diradicals is discussed. The state reordering is shown to be responsible for the prediction that the substitution of the oxygens in NQ for the CH2 groups in NQDM increases, rather than decreases, the singlet-triplet energy separation (EST).

Authors:
ORCiD logo [1]; ORCiD logo [2]; ORCiD logo [1]
  1. Department of Chemistry and the Center for Advanced, Scientific Computing and Modeling, University of North Texas, Denton TX USA
  2. Physical Sciences Division, Pacific Northwest National Laboratory, Richland WA USA
Publication Date:
Research Org.:
Pacific Northwest National Lab. (PNNL), Richland, WA (United States)
Sponsoring Org.:
USDOE
OSTI Identifier:
1508275
Report Number(s):
PNNL-SA-131464
Journal ID: ISSN 0894-3230
DOE Contract Number:  
AC05-76RL01830
Resource Type:
Journal Article
Journal Name:
Journal of Physical Organic Chemistry
Additional Journal Information:
Journal Volume: 31; Journal Issue: 8; Journal ID: ISSN 0894-3230
Country of Publication:
United States
Language:
English

Citation Formats

Hrovat, David A., Wang, Xue-Bin, and Borden, Weston Thatcher. Calculations of the relative energies of the low-lying electronic states of 2,7-naphthoquinodimethane and 2,7-naphthoquinone. Substitution of oxygen for CH 2 is predicted to increase the singlet-triplet energy difference ( ΔE ST ). United States: N. p., 2018. Web. doi:10.1002/poc.3824.
Hrovat, David A., Wang, Xue-Bin, & Borden, Weston Thatcher. Calculations of the relative energies of the low-lying electronic states of 2,7-naphthoquinodimethane and 2,7-naphthoquinone. Substitution of oxygen for CH 2 is predicted to increase the singlet-triplet energy difference ( ΔE ST ). United States. doi:10.1002/poc.3824.
Hrovat, David A., Wang, Xue-Bin, and Borden, Weston Thatcher. Tue . "Calculations of the relative energies of the low-lying electronic states of 2,7-naphthoquinodimethane and 2,7-naphthoquinone. Substitution of oxygen for CH 2 is predicted to increase the singlet-triplet energy difference ( ΔE ST )". United States. doi:10.1002/poc.3824.
@article{osti_1508275,
title = {Calculations of the relative energies of the low-lying electronic states of 2,7-naphthoquinodimethane and 2,7-naphthoquinone. Substitution of oxygen for CH 2 is predicted to increase the singlet-triplet energy difference ( ΔE ST )},
author = {Hrovat, David A. and Wang, Xue-Bin and Borden, Weston Thatcher},
abstractNote = {CASSCF and CASPT2 calculations have been performed on the triplet and two lowest-lying singlet states of the 2,7-naphthoquinodimethane (NQDM) and 2,7-naphthoquinone (NQ) diradicals. Both diradicals are predicted to have triplet ground states but to differ in the ordering of the two lowest singlet states, with E(1A1) < E(1B2) in NQDM, but E(1A1) > E(1B2) in NQ. The reason for the difference in ordering of the singlet states in these two diradicals is discussed. The state reordering is shown to be responsible for the prediction that the substitution of the oxygens in NQ for the CH2 groups in NQDM increases, rather than decreases, the singlet-triplet energy separation (EST).},
doi = {10.1002/poc.3824},
journal = {Journal of Physical Organic Chemistry},
issn = {0894-3230},
number = 8,
volume = 31,
place = {United States},
year = {2018},
month = {2}
}