MD-Simulation of Site Geometries and Photoinduced Site Interconversion of Diphenylacetylene (Tolan) in an Argon Matrix

摘要

The absorption spectra of tolan in an argon matrix indicate the presence of several matrix species (sites). Selective laser excitation of individual sites results in persistent spectral holes. The formation of Argon crystals with tolan impurities has been simulated by statistical molecular dynamics calculations. A large number of sites could be generated and classified as defect structures related to four ideal substitutional sites. Trajectory calculations following activation of the internal rotation of tolan showed that the molecule can relax to a different conformer accompanied by a rearrangement of the cage of host atoms. This corresponds to site-interconversion and gives a plausible photophysical mechanism for spectral hole-burning.