title: Pressure-tuning micro-Raman spectra of artists' pigments: α- and β-copper phthalocyanine polymorphs.
abstract: The two polymorphs of copper phthalocyanine, α- and β-CuPc, have been examined by micro-Raman spectroscopy at pressures approaching 5.0 GPa. The metastable α-polymorph does not exhibit any structural changes, while the more thermodynamically stable β-polymorph does exhibit a reversible phase transition at 2.0 GPa. The pressure dependences (dν/dP) for a selected number of vibrational modes are reported. Two regions of the Raman spectra, 800-900 cm(-1) and 1100-1200 cm(-1), are sensitive to pressure such that they can be used as indicators of the polymorphic form.
authors: Department of Chemistry, McGill University, 801 Sherbrooke St. West, Montreal, Quebec H3A 0B8, Canada.
authors: Guillaume
authors: G
authors: Beaulieu-Houle
authors: Denis F R
authors: DF
authors: Gilson
authors: Ian S
authors: IS
authors: Butler
mesh_terms: D001154:Art; D004396:Coloring Agents / Q000032:analysis*; D007211:Indoles / Q000737:chemistry*; D009942:Organometallic Compounds / Q000737:chemistry*; D010150:Paint / Q000032:analysis*; D044367:Phase Transition; D011312:Pressure; D013059:Spectrum Analysis, Raman; D013816:Thermodynamics; D014732:Vibration
chemical_list: D004396:Coloring Agents; D007211:Indoles; D009942:Organometallic Compounds; C015445:copper phthalocyanine
keywords: Artists’ pigments; Copper phthalocyanines; High-pressure; Phase transition; Raman spectroscopy