Τίτλος:
Low-frequency Raman spectroscopy of n-alcohols. LAM vibration and crystal structure
Γλώσσες Τεκμηρίου:
Αγγλικά
Περίληψη:
Low-frequency Raman spectra of even and odd n-alcohols have been recorded. The longitudinal acoustic modes (LAM) are described, and the effects of hydrogen-bonding, chain length, and temperature on the frequencies of these vibrations are discussed. The frequencies of the LAMs are interpreted in terms of the one-dimensional crystal model of Minoni and Zerbi and also ab initio calculations on isolated single chains. The low-frequency LAM-1 mode of the hydrogen-bonded dimer exhibited an odd-even effect, and to gain insight into this, the crystal structures of the C17 and C20 alcohols were determined by single-crystal X-ray diffractometry. C17H35OH packs in the β form, with half the oxygen atoms trans and half gauche, with respect to the alkyl chains. C20H41OH adopts an all trans conformation and the packing is in the γ form. The hydrogen-bonding interactions differ in the two structures. We therefore ascribe the odd-even effect in the LAM-1 frequencies to an odd-even effect in crystal structure.
Συγγραφείς:
Soutzidou, M.
Glezakou, V.-A.
Viras, K.
Helliwell, M.
Masters, A.J.
Vincent, M.A.
Περιοδικό:
JOURNAL OF PHYSICAL CHEMISTRY B: CONDENSED MATTER, MATERIALS, SURFACES, INTERFACES, AND BIOPHYSICAL (THE)
Λέξεις-κλειδιά:
Longitudinal acoustic modes (LAM), Crystal structure; Dimers; Hydrogen bonds; Raman spectroscopy, Alcohols
