Effect of High Pressure on Vibrational Modes of Polyiodides in Poly(vinyl alcohol) Films

Autor:	Edward L. Quitevis, Mark Holtz, Archita Sengupta
Rok vydání:	1997
Předmět:	Vinyl alcohol Scattering Stereochemistry Exciton Overtone Hydrostatic pressure Molecular physics Surfaces Coatings and Films chemistry.chemical_compound Polyiodide chemistry Molecular vibration Materials Chemistry Molecule Physical and Theoretical Chemistry
Zdroj:	The Journal of Physical Chemistry B. 101:11092-11098
ISSN:	1520-5207 1520-6106
Popis:	We have used resonance-Raman scattering to study the effects of hydrostatic pressure (to 80 kbar) on polyiodide chain vibrations in iodine-doped poly(vinyl alcohol) films. Two strong fundamental bands are observed along with overtone and combination bands. The low-energy band at 107 cm-1 is attributed to symmetric stretching of I3-. The higher lying band at 154 cm-1 is from symmetric stretching of the two end I2 units in I5-. The I3- and I5- are intermixed within the polyiodide chains. The combination band arises from exciton coupling between molecules within the chains. Three primary effects are observed with increasing pressure. First, the Raman band at 107 cm-1 blue shifts under pressure, while the band at 154 cm-1 shifts weakly. This latter is attributed to the competing effects of compression, enhanced interaction of the outer I2 with the central I- (which weakens the outer I−I bond), and attractive host−guest interactions which increase in strength with compression. The second effect observed in the...
Databáze:	OpenAIRE
Externí odkaz:	https://explore.openaire.eu/search/publication?articleId=doi_________::37871455060f9efcbfcca679d6b55f6e https://doi.org/10.1021/jp972898t Zobrazit plný text záznamu