OBSERVATION OF ELECTRIC-DIPOLE-FORBIDDEN STATES IN POLYDIACETYLENE BYMEANS OF 2ND-HARMONIC GENERATION SPECTROSCOPY

Authors
MANAKA T YAMADA T HOSHI H ISHIKAWA K TAKEZOE H FUKUDA A
Citation
T. Manaka et al., OBSERVATION OF ELECTRIC-DIPOLE-FORBIDDEN STATES IN POLYDIACETYLENE BYMEANS OF 2ND-HARMONIC GENERATION SPECTROSCOPY, Synthetic metals, 84(1-3), 1997, pp. 963-964
Citations number
12
Categorie Soggetti
Physics, Condensed Matter","Material Science","Polymer Sciences
Journal title
Synthetic metals → ACNP
ISSN journal
03796779
Volume
84
Issue
1-3
Year of publication
1997
Pages
963 - 964
Database
ISI
SICI code
0379-6779(1997)84:1-3<963:OOESIP>2.0.ZU;2-7
Abstract
We have observed second-harmonic generation (SHG) and third-harmonic g eneration (THG) spectra in polydiacetylene (PDA), poly[5,7-dodecadiyne -1,12-diyl-bis-ethylurethane], thin films. According to linear absorpt ion and THG spectra in PDA, two dipole-allowed states, the lowest B-u exciton and the band edge, exist around 2.0 eV and 2.6 eV, respectivel y. Therefore, a resonant peak appearing around 2.35 eV in SHG and THG spectra is due to the dipole-forbidden A(g) exciton state. Thus, the S HG spectroscopy serves as a powerful tool for investigating dipole-for bidden states as much as THG spectroscopy.