کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
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245304 | 501987 | 2007 | 11 صفحه PDF | دانلود رایگان |
IR (infrared) line shapes of OH stretching bands in hydrogen-bonding states of ethanol–hexane solutions have been examined using a theoretically rigorous Voigt function, instead of the commonly used empirical Lorentz–Gauss equation. An efficient and numerically-stable computer code with the Voigt function has been developed in order to analyze hydrogen-bonding effects in IR absorption spectra. Although the Voigt function is not an analytically-closed form, a numerical computer subroutine, with only three adjustable parameters for each IR band (or peak), provides a unique solution in a least-squares analysis of the line shapes. On the other hand, the Lorentz–Gauss equation is an analytical function with four adjustable parameters for each IR peak. However, this function makes non-linear least-squares analyses almost impossible due to the existence of strong correlations among the parameters. Example analyses, using the ethanol–hexane system, are given. The degree of hydrogen-bonding associations of ethanol and an effective IR-absorbance coefficient for hydrogen-bonded clusters have been estimated, and results are quite reasonable, compared with those in the literature.
Journal: Applied Energy - Volume 84, Issue 9, September 2007, Pages 863–873