TY - JOUR
T1 - Low-frequency Raman spectroscopy of n-alcohols. LAM vibration and crystal structure
AU - Soutzidou, Maria
AU - Glezakou, Vassiliki Alexandra
AU - Viras, Kyriakos
AU - Helliwell, Madeleine
AU - Masters, Andrew J.
AU - Vincent, Mark A.
PY - 2002/5/2
Y1 - 2002/5/2
N2 - 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.
AB - 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.
UR - http://www.scopus.com/inward/record.url?scp=0037007805&partnerID=8YFLogxK
U2 - 10.1021/jp025586l
DO - 10.1021/jp025586l
M3 - Article
AN - SCOPUS:0037007805
SN - 1089-5647
VL - 106
SP - 4405
EP - 4411
JO - Journal of Physical Chemistry B
JF - Journal of Physical Chemistry B
IS - 17
ER -