title: A high pressure FT-IR spectroscopic study of phase transitions in 1-chloro- and 1-bromoadamantane.
abstract: The infrared spectra of two orientationally disordered adamantane derivatives, 1-chloro- and 1-bromoadamantane, have been obtained as a function of pressure by use of a diamond anvil cell. Phase transitions were detected from the splittings of vibrational bands and from changes in the slopes on plots of frequency versus pressure. In 1-chloroadamantane, a disorder-order phase transition was detected at approximately 5 kbar. This high-pressure phase is identical to the ordered phase obtained at low temperature. A second phase transition at high pressure was identified, for the first time, at approximately 17 kbar. The new high-pressure phase is an ordered phase. For 1-bromoadamantane, a semi-ordered to ordered phase transition was detected at about 5 kbar, and no other transitions were observed up to a pressure of 35 kbar. For both derivatives, the phase changes were reversible.
authors.affiliation: Department of Chemistry, The University of Western Ontario, London, Canada.
authors.forename: L A
authors.initials: LA
authors.lastname: Fraczyk
authors.forename: Y
authors.initials: Y
authors.lastname: Huang
mesh_terms: D000218:Adamantane / Q000031:analogs & derivatives* / Q000737:chemistry; D011312:Pressure; D017550:Spectroscopy, Fourier Transform Infrared
chemical_list: D000218:Adamantane