+ Site Statistics
+ Search Articles
+ Subscribe to Site Feeds
EurekaMag Most Shared ContentMost Shared
EurekaMag PDF Full Text ContentPDF Full Text
+ PDF Full Text
Request PDF Full TextRequest PDF Full Text
+ Follow Us
Follow on FacebookFollow on Facebook
Follow on TwitterFollow on Twitter
Follow on LinkedInFollow on LinkedIn

+ Translate

Vibronic coupling in asymmetric bichromophores: experimental investigation of diphenylmethane-d₅

Vibronic coupling in asymmetric bichromophores: experimental investigation of diphenylmethane-d₅

Journal of Chemical Physics 141(6): 064316-064316

Vibrationally and rotationally resolved electronic spectra of diphenylmethane-d5 (DPM-d5) are reported in the isolated-molecule environment of a supersonic expansion. While small, the asymmetry induced by deuteration of one of the aromatic rings is sufficient to cause several important effects that change the principle mechanism of vibronic coupling between the close-lying S1 and S2 states, and spectroscopic signatures such coupling produces. The splitting between S1 and S2 origins is 186 cm(-1), about 50% greater than its value in DPM-d0 (123 cm(-1)), and an amount sufficient to bring the S2 zero-point level into near-resonance with the v = 1 level in the S1 state of a low-frequency phenyl flapping mode, ν(R) = 191 cm(-1). Dispersed fluorescence spectra bear clear evidence that Δv(R) = 1 Herzberg-Teller coupling dominates the near-resonant internal mixing between the S1 and S2 manifolds. The fluorescence into each pair of Franck-Condon active ring modes shows an asymmetry that suggests incorrectly that the S1 and S2 states may be electronically localized. From rotationally resolved studies, the S0 and S1 states have been well-fit to asymmetric rotor Hamiltonians while the S2 state is perturbed and not fit. The transition dipole moment (TDM) orientation of the S1 state is nearly perpendicular to the C2 symmetry axes with 66(2)%:3(1)%:34(2)% a:b:c hybrid-type character while that of the S2 origin contains 50(10)% a:c-type (S1) and 50(10)% b-type (S2) character. A model is put forward that explains qualitatively the TDM compositions and dispersed emission patterns without the need to invoke electronic localization. The experimental data discussed here serve as a foundation for a multi-mode vibronic coupling model capable of being applied to asymmetric bichromophores, as presented in the work of B. Nebgen and L. V. Slipchenko ["Vibronic coupling in asymmetric bichromophores: Theory and application to diphenylmethane-d5," J. Chem. Phys. (submitted)].

(PDF emailed within 0-6 h: $19.90)

Accession: 056869412

Download citation: RISBibTeXText

PMID: 25134580

DOI: 10.1063/1.4892344

Related references

Vibronic coupling in asymmetric bichromophores: theory and application to diphenylmethane-d(5). Journal of Chemical Physics 141(13): 134119-134119, 2014

Vibronic coupling in asymmetric bichromophores: theory and application to diphenylmethane. Journal of Chemical Physics 137(8): 084112-084112, 2013

Vibronic coupling in cyclopentadienyl radical: a method for calculation of vibronic coupling constant and vibronic coupling density analysis. Journal of Chemical Physics 124(2): 024314-024314, 2006

Vibronic coupling in benzene cation and anion: vibronic coupling and frontier electron density in Jahn-Teller molecules. Journal of Chemical Physics 124(15): 154303-154303, 2006

Vibronic coupling in naphthalene anion: vibronic coupling density analysis for totally symmetric vibrational modes. Journal of Physical Chemistry. A 112(4): 758-767, 2008

Chemical reactivity in nucleophilic cycloaddition to C70: vibronic coupling density and vibronic coupling constants as reactivity indices. Journal of Organic Chemistry 77(21): 9702-9706, 2012

Vibronic Coupling Investigation to Compute Phosphorescence Spectra of Pt(II) Complexes. Inorganic Chemistry 54(11): 5588-5595, 2015

Conformer-specific vibronic spectroscopy and vibronic coupling in a flexible bichromophore: bis-(4-hydroxyphenyl)methane. Journal of Chemical Physics 134(16): 164312-164312, 2011

Analysis of the S2←S0 vibronic spectrum of the ortho-cyanophenol dimer using a multimode vibronic coupling approach. Journal of Chemical Physics 142(8): 084308-084308, 2016

A method to reduce the size of the vibronic basis employed in the simulation of spectra using the multimode vibronic coupling approximation. Journal of Chemical Physics 128(4): 044119-044119, 2008

Vibronic coupling in indole: II. Investigation of the 1La-1Lb interaction using rotationally resolved electronic spectroscopy. Physical Chemistry Chemical Physics 12(19): 4980-4988, 2010

Vibronic coupling in dicyano-complex-bridged mixed-valence complexes. Relaxation of vibronic constraints in systems with degenerate bridging-ligand and electron-transfer excited states. Inorganic Chemistry 39(3): 437-446, 2001

The S1/S2 exciton interaction in 2-pyridone·6-methyl-2-pyridone: Davydov splitting, vibronic coupling, and vibronic quenching. Journal of Chemical Physics 135(15): 154311-154311, 2011

Vibronic coupling to simulate the phosphorescence spectra of Ir(III)-based OLED systems: TD-DFT results meet experimental data. Journal of Molecular Modeling 22(11): 265-265, 2016

Vibronic structure and ion core interactions in Rydberg states of diazomethane: an experimental and theoretical investigation. Journal of Physical Chemistry. A 111(51): 13347-13357, 2007