Display options
Share it on

Chemphyschem. 2016 Oct 05;17(19):3129-3138. doi: 10.1002/cphc.201600650. Epub 2016 Aug 18.

Excited States of Xanthene Analogues: Photofragmentation and Calculations by CC2 and Time-Dependent Density Functional Theory.

Chemphyschem : a European journal of chemical physics and physical chemistry

Alexander Jan Kulesza, Evgenii Titov, Steven Daly, Radosław Włodarczyk, Jörg Megow, Peter Saalfrank, Chang Min Choi, Luke MacAleese, Rodolphe Antoine, Philippe Dugourd

Affiliations

  1. Univ Lyon, Université Claude Bernard Lyon 1, CNRS, Institut Lumière Matière, F-69622, Lyon, France. [email protected].
  2. Universität Potsdam, Institut für Chemie, Karl-Liebknecht-Straße 24-25, Haus 25, D-14476, Potsdam, Germany.
  3. Univ Lyon, Université Claude Bernard Lyon 1, CNRS, Institut Lumière Matière, F-69622, Lyon, France.

PMID: 27428813 DOI: 10.1002/cphc.201600650

Abstract

Action spectroscopy has emerged as an analytical tool to probe excited states in the gas phase. Although comparison of gas-phase absorption properties with quantum-chemical calculations is, in principle, straightforward, popular methods often fail to describe many molecules of interest-such as xanthene analogues. We, therefore, face their nano- and picosecond laser-induced photofragmentation with excited-state computations by using the CC2 method and time-dependent density functional theory (TDDFT). Whereas the extracted absorption maxima agree with CC2 predictions, the TDDFT excitation energies are blueshifted. Lowering the amount of Hartree-Fock exchange in the DFT functional can reduce this shift but at the cost of changing the nature of the excited state. Additional bandwidth observed in the photofragmentation spectra is rationalized in terms of multiphoton processes. Observed fragmentation from higher-lying excited states conforms to intense excited-to-excited state transitions calculated with CC2. The CC2 method is thus suitable for the comparison with photofragmentation in xanthene analogues.

© 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Keywords: CC2 calculations; density functional calculations; multiphoton processes; photofragmentation; xanthenes

Publication Types