Hirayama spectra

Several reports have appeared in which the UV absorption spectrum of PS was found to be qualitatively similar to an alkyl benzene model compound. Vala and Rice15> demonstrated the similarity between atactic PS and ethyl benzene this was confirmed for atactic PS in cyclohexane by Hirayama 16) and in tetrahydrofuran by Abuin 17>. Bovey and co-workers20) found that absorbance spectra for isotactic PS, atactic PS, and styrene-methylmethacrylate copolymers in 1,2-dichloroethane were roughly similar to that of toluene. 

Mori K, IjimaM, KoikeH, Hattoii N, TamakaE, WatanabeH, Katsuno M, Fujita A, Aiba I, Ogata A, Saito T, Asakura K, Yoshida A, Hirayama M, Sobue G (2005) The wide spectrum of clinical man-ifestadons in Sjogren s syndrome associated neuropadiy. Brain 128(11) 2518-1534. 

Direct observation of fluorescence from higher singlet states of benzene and some methyl derivatives has recently been achieved by Hirayama, Gregory, and Lipsky (247). Using apparatus capable of detecting fluorescence yields as low as 10 they recorded the emission spectra from oxygenated solutions of pure benzene and other aromatics excited at 184.9 nm. Subtraction of the tail of the residual S, emission gives a fluorescence spectrum with approximately 235 nm and = 8 x 10 for... 

Hirayama and Lipsky have extended their observations of weak fluorescence from unlikely candidates for luminescence by examining propylene, 1-butene, -2-butene, fra -2-butene, 1-hexene, -2-hexene, tra/z.s-2-hexene, 2-methyl-pentene, and 2,3-dimethyl-2-butene excited at 184.9 nm in the vapour and liquid phases.328 Quantum yields in general were of the order of 10-8, and fluorescence observed was in the 35 000—50 000 cm-1 region of the spectrum. The authors... 

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