https://doi.org/10.1140/epjd/e2005-00139-0
Negative ion photoelectron spectroscopy of 2,2'-bithiophene cluster anions, (2T)n- (n = 1–100)
1
Department of Chemistry, Faculty of Science and Technology, Keio
University, 3-14-1 Hiyoshi, Kohoku-ku, Yokohama 223-8522, Japan
2
CREST, Japan Science and Technology Agency, c/o Department of
Chemistry, Keio University, Yokohama 223-8522, Japan
Corresponding author: a nakajima@chem.keio.ac.jp
Received:
6
September
2004
Published online:
13
July
2005
Cluster anions of 2,2'-bithiophene, (2T)
, were produced up
to 
in the gas-phase. The energetics of the excess electron in
the (2T) clusters with 
were explored by
negative ion photoelectron spectroscopy. When the vertical detachment
energies (VDEs) obtained from the photoelectron spectra were analyzed by a
plot against 
, it has been revealed that the excess electron
trapping level thus extrapolated is located at 
0.8 eV below the
conduction band minimum (i.e. LUMO) of the 2T thin film. The large slope of
the VDEs vs. plot suggests that the neutral 2T molecules
surrounding the anion core take non-planar twisted conformations with
permanent dipole moments, resulting in the exceedingly deep trapping of the
excess electron in the 2T cluster anions.
PACS: 36.40.-c – Atomic and molecular clusters / 36.40.Wa – Charged clusters
© EDP Sciences, Società Italiana di Fisica, Springer-Verlag, 2005
