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POLARIZED UV‐ABSORPTION SPECTRA OF RETINAL ISOMERS‐I. MEASUREMENTS IN EXTREMELY THIN MONOCRYSTAL PLATELETS
Author(s) -
Drikos G.,
Rüppel H.,
Sperling W.,
Morys P.
Publication year - 1984
Publication title -
photochemistry and photobiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.818
H-Index - 131
eISSN - 1751-1097
pISSN - 0031-8655
DOI - 10.1111/j.1751-1097.1984.tb04558.x
Subject(s) - crystal (programming language) , spectral line , retinal , absorption spectroscopy , absorption (acoustics) , absorption band , quartz , wavenumber , materials science , chemistry , optics , analytical chemistry (journal) , physics , biochemistry , astronomy , computer science , composite material , programming language , chromatography
Crystals of all‐ trans retinal and both different forms of 11‐ cis , 12‐s‐ cis retinal were grown on quartz slides with faces (101), (001) and (101), respectively, forming thin platelets of less than 0.2 μm thickness. Polarized UV absorption spectra at room temperature were measured in the range from 20 to 43 × 10 3 cm −1 with a microscope‐spectrophotometer. In this spectral range three diffuse absorption bands were observed for all crystal types at similar wave numbers. A main absorption band was found at 25–28 × 10 3 cm −1 , and two further bands at 32–34 and 38–40 × 10 3 cm −1 . In case of all‐ trans retinal the latter band is by far the weakest in this spectral range. Additionally, the crystal spectrum of all‐ trans retinal shows a shoulder at the low wavenumber side of the main band which cannot be resolved in the corresponding solution spectrum. In the crystal spectra of 11‐ cis , 12‐s‐ cis retinal, however, only a strong dissymmetry is observed at this side of the main band.