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T 1 , T 2 State Energies and Electron Affinities of Small α,ω‐Diphenylpolyenes Investigated by Anion Photodetachment Photoelectron Spectroscopy and Excited‐State Theory
Author(s) -
Vogeler Ferdinand,
Siegert Swen,
Marian Christel M.,
Weinkauf Rainer
Publication year - 2011
Publication title -
chemphyschem
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.016
H-Index - 140
eISSN - 1439-7641
pISSN - 1439-4235
DOI - 10.1002/cphc.201001083
Subject(s) - x ray photoelectron spectroscopy , affinities , excited state , ion , spectroscopy , electron affinity (data page) , chemistry , atomic physics , electron , state (computer science) , electron spectroscopy , physics , stereochemistry , molecule , nuclear magnetic resonance , organic chemistry , quantum mechanics , algorithm , computer science
Photodetachment photoelectron spectroscopy (PD‐PES) on molecular radical anions provides electron affinities and direct spectroscopic access to the lowest triplet states T 1 and T 2 of the corresponding neutral molecules. Herein, we apply this method to investigate trans ‐stilbene (SB), all‐ trans ‐1,4‐diphenyl‐1,3‐butadiene (DPB), and all‐ trans ‐1,6‐diphenyl‐1,3,5‐hexatriene (DPH). Our gas‐phase T 1 energies agree with previous measurements on condensed crystals. The T 2 state energies are determined in this work for the first time. Experimental electron affinities, neutral excited‐state transition energies and intensities are compared to theoretical data calculated by using DFT (ground states) or DFT/MRCI (excited states) methods. We give an explanation why intersystem crossing is of minor importance in all three compounds although the T 2 states are situated close below the S1 states.