Phase-specific Raman analysis of n-alkane melting by moving-window two-dimensional correlation spectroscopy

Published

November 9, 2016

Author(s)

Ying Jin, Anthony Kotula, Angela R. Hight Walker, Kalman D. Migler, Young Jong Lee

Abstract

We usemoving-window two-dimensional correlation spectroscopy (MW-2DCOS) for phase-specific Raman analysis of the n-alkane (C21H44) duringmelting from the crystalline solid phase to the intermediate rotator phase and to the amorphousmolten phase. In MW-2DCOS, individual peak-to- peak correlation analysis within a small subset of spectra provides both temperature-resolved and spectrally disentangled Raman assignments conducive to understanding phase-specific molecular interactions and chain configurations. We demonstrate that autocorrelationMW-2DCOS can determine the phase transition temperatures with a higher resolving power than commonly used analysis methods including individual peak intensity analysis or principal component analysis. Besides the enhanced temperature resolving power, we demonstrate that asynchronous 2DCOS near the orthorhombicto-rotator transition temperature can spectrally resolve the two overlapping peaks embedded in the Raman CH2 twisting band in the orthorhombic phase, which had been only predicted but not observed because of thermal broadening near the melting temperature.

Citation

Journal of Raman Spectroscopy

Volume

47

Issue

11

Pub Type

Journals

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Keywords

Raman, alkane, phase transition, melting, 2DCOS

Citation

Jin, Y. , Kotula, A. , Hight Walker, A. , Migler, K. and Lee, Y. (2016), Phase-specific Raman analysis of n-alkane melting by moving-window two-dimensional correlation spectroscopy, Journal of Raman Spectroscopy, [online], https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=920294 (Accessed December 8, 2024)