If you are experiencing problems downloading PDF or HTML fulltext, our helpdesk recommend clearing your browser cache and trying again. If you need help in clearing your cache, please click here . Still need help? Email help@ingentaconnect.com

Temperature-Dependent Raman Study of the Smectic to Nematic Phase Transition and Vibrational Analysis Using Density Functional Theory of the Liquid Crystalline System 4-Decyloxy Benzoic Acid

$29.00 plus tax (Refund Policy)

Buy Article:

Abstract:

Room-temperature Raman spectra of the thermotropic liquid crystalline system, 4-decyloxy benzoic acid (4DBA) have been recorded and the experimentally observed bands are assigned by density functional theory (DFT) for the first time. The C–O and C–C stretching and C–H in-plane bending modes of the phenyl ring and C=O stretching modes of the –COOH group are the marker bands for the smectic (S) → nematic (N) and nematic (N) → isotropic (I) transitions for this system. The temperature-dependent Raman spectra for these bands in the heating cycle clearly characterize the S→N and the N→I transition over a range <1 °C, which is much better than the earlier range of 23 °C for S→N and 26 °C for the N→I transition. The ∼773, ∼807, ∼881, and ∼1146 cm–1 bands disappear, whereas a band at ; 830 cm–1 appears at the S→N transition. The relative intensity of the ∼1257 and ∼1280 cm–1 bands distinguishes the three phases, namely smectic, nematic, and isotropic, in 4DBA. The variation of line width and peak wavenumber of the ∼1128 and ∼1168 cm–1 bands also clearly shows the two transitions. The molecular reorientation at the transition and the effect of local fields present in the liquid crystalline mesophases are also briefly discussed on the basis of changes in intensity, linewidth and peak wavenumber with temperature.

Keywords: 4-DECYLOXY BENZOIC ACID; 4DBA; DENSITY FUNCTIONAL THEORY; DFT; NEMATIC; RAMAN SPECTROSCOPY; SMECTIC

Document Type: Research Article

DOI: http://dx.doi.org/10.1366/000370210790619546

Affiliations: 1: Department of Physics, Banaras Hindu University, Varanasi-221005, India 2: Institut für Physikalische Chemie, Friedrich-Schiller-Universität, Helmholtzweg4, D-07743 Jena, Germany 3: Department of Physics, Banaras Hindu University, Varanasi-221005, India. Email: ranjanksingh65@rediffmail.com

Publication date: February 1, 2010

More about this publication?
Related content

Tools

Favourites

Share Content

Access Key

Free Content
Free content
New Content
New content
Open Access Content
Open access content
Subscribed Content
Subscribed content
Free Trial Content
Free trial content
Cookie Policy
X
Cookie Policy
ingentaconnect website makes use of cookies so as to keep track of data that you have filled in. I am Happy with this Find out more