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Influence of molecular geometry, exchange-correlation functional, and solvent effects in the modeling of vertical excitation energies in phthalocyanines using time-dependent density functional theory (TDDFT) and polarized continuum model TDDFT methods: can modern computational chemistry methods explain experimental controversies?

Nemykin, Victor N. and Hadt, Ryan G. and Belosludov, Rodion V. and Mizuseki, Hiroshi and Kawazoe, Yoshiyuki (2007) Influence of molecular geometry, exchange-correlation functional, and solvent effects in the modeling of vertical excitation energies in phthalocyanines using time-dependent density functional theory (TDDFT) and polarized continuum model TDDFT methods: can modern computational chemistry methods explain experimental controversies? Journal of Physical Chemistry A, 111 (50). pp. 12901-12913. ISSN 1089-5639. https://resolver.caltech.edu/CaltechAUTHORS:20180612-161522631

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Abstract

A time-dependent density functional theory (TDDFT) approach coupled with 14 different exchange-correlation functionals was used for the prediction of vertical excitation energies in zinc phthalocyanine (PcZn). In general, the TDDFT approach provides a more accurate description of both visible and ultraviolet regions of the UV-vis and magnetic circular dichroism (MCD) spectra of PcZn in comparison to the more popular semiempirical ZINDO/S and PM3 methods. It was found that the calculated vertical excitation energies of PcZn correlate with the amount of Hartree-Fock exchange involved in the exchange-correlation functional. The correlation was explained on the basis of the calculated difference in energy between occupied and unoccupied molecular orbitals. The influence of PcZn geometry, optimized using different exchange-correlation functionals, on the calculated vertical excitation energies in PcZn was found to be relatively small. The influence of solvents on the calculated vertical excitation energies in PcZn was considered for the first time using a polarized continuum model TDDFT (PCM-TDDFT) method and was found to be relatively small in excellent agreement with the experimental data. For all tested TDDFT and PCM-TDDFT cases, an assignment of the Q-band as an almost pure a_(1u) (HOMO)-->e_g (LUMO) transition, initially suggested by Gouterman, was confirmed. Pure exchange-correlation functionals indicate the presence of six ^1_Eu states in the B-band region of the UV-vis spectrum of PcZn, while hybrid exchange-correlation functionals predict only five ^1E_u states for the same energy envelope. The first two symmetry-forbidden n-->pi* transitions were predicted in the Q0-2 region and in the low-energy tail of the B-band, while the first two symmetry-allowed n-->π* transitions were found within the B-band energy envelope when pure exchange-correlation functionals were used for TDDFT calculations. The presence of a symmetry-forbidden but vibronically allowed n-->π* transition in the Q_(0-2) spectral envelope explains the long-time controversy between the experimentally observed low-intensity transition in the Q_(0-2) region and previous semiempirical and TDDFT calculations, which were unable to predict any electronic transitions in this area. To prove the conceptual possibility of the presence of several degenerate ^1E_u states in the B-band region of PcZn, room-temperature UV-vis and MCD spectra of zinc tetra-tert-butylphthalocyanine (Pc^tZn) in non-coordinating solvents were recorded and analyzed using band deconvolution analysis. It was found that the B-band region of the UV-vis and MCD spectra of Pc^tZn can be easily deconvoluted using six MCD Faraday A-terms and two MCD Faraday B-terms with energies close to those predicted by TDDFT calculations for ^1E_u and ^1A_(2u) excited states, respectively. Such a good agreement between theory and experiment clearly indicates the possibility of employing a TDDFT approach for the accurate prediction of vertical excitation energies in phthalocyanines within a large energy range.


Item Type:Article
Related URLs:
URLURL TypeDescription
https://doi.org/10.1021/jp0759731DOIArticle
https://pubs.acs.org/doi/suppl/10.1021/jp0759731PublisherSupporting Information
ORCID:
AuthorORCID
Hadt, Ryan G.0000-0001-6026-1358
Additional Information:© 2007 American Chemical Society. Received: July 27, 2007; In Final Form: September 11, 2007. Generous support from the Donors of Petroleum Research Fund, administrated by the American Chemical Society (Grant No. PRF-45510-GB-3 to V.N.), Research Corporation Cottrell College Science Award (Grant No. CC6766), University of Minnesota Grant-in-Aid (Grant No. 20209), and Minnesota Supercomputing Institute to V. N. as well as University of Minnesota Duluth Undergraduate Research Opportunity Grants to R. H. are greatly appreciated. R.V.B., H.M., and Y.K. thank the Information Science Group of IMR, Tohoku University, for their continuous support of the SR11000 Supercomputing System, and the Ministry of Education, Culture, Sports, Science, and Technology of Japan (Grant No. 17686072) for financial support. We also acknowledge Professor Barry Lever for illuminating discussions.
Funders:
Funding AgencyGrant Number
American Chemical Society Petroleum Research FundPRF-45510-GB-3
Cottrell Scholar of Research CorporationCC6766
University of Minnesota Duluth20209
Minnesota Supercomputing InstituteUNSPECIFIED
Ministry of Education, Culture, Sports, Science and Technology (MEXT)17686072
Issue or Number:50
Record Number:CaltechAUTHORS:20180612-161522631
Persistent URL:https://resolver.caltech.edu/CaltechAUTHORS:20180612-161522631
Official Citation:Influence of Molecular Geometry, Exchange-Correlation Functional, and Solvent Effects in the Modeling of Vertical Excitation Energies in Phthalocyanines Using Time-Dependent Density Functional Theory (TDDFT) and Polarized Continuum Model TDDFT Methods:  Can Modern Computational Chemistry Methods Explain Experimental Controversies? Victor N. Nemykin, Ryan G. Hadt, Rodion V. Belosludov, Hiroshi Mizuseki, and Yoshiyuki Kawazoe The Journal of Physical Chemistry A 2007 111 (50), 12901-12913 DOI: 10.1021/jp0759731
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:87041
Collection:CaltechAUTHORS
Deposited By: George Porter
Deposited On:13 Jun 2018 14:35
Last Modified:03 Oct 2019 19:51

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