Linearity between Structural Correlation Length and Correlated-Proton Raman Intensity from Amorphous Ice and Supercooled Water up to Dense Supercritical Steam
Linearity between Structural Correlation Length and Correlated-Proton Raman Intensity from Amorphous Ice and Supercooled Water up to Dense Supercritical Steam
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DOI：
10.1021/j100028a025
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发表时间：
1995-07
期刊：
影响因子：
--
通讯作者：
G. Walrafen;Y. Chu
中科院分区：
文献类型：
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作者：
G. Walrafen;Y. Chu
由径向分布函数得到的结构关联长度(SCL)在-163℃低密度无定形(LDA)冰、过冷水和环境水以及高达401C和1730bar的超临界水的关联和非关联质子OH伸缩带的积分拉曼强度比中呈线性关系。这种线性度，从-163℃到？400℃，是因为质子运动在氢键距离上相关，这是由SCL确定的。此外，最长的声学声子波长，即TA或切变模的波长，出现在？55 cm-1，1·2附近，也完全受SCL的限制。因此，质子(OH伸展)和质心(TA声子)关联都源于氢键聚集体或碎片的大小，并在距离上受到其大小的限制。LDA冰在线性关系中的包含也表明从无定形冰到过冷水的状态可能是连续的，而当大多数氢键被破坏时，则达到高温、超临界极限。
Structural correlation lengths (SCL) obtained from radial distribution functions were found to be linear in the integrated Raman intensity ratios of the correlated-to uncorrelated-proton OH stretching bands from—163 C, low-density amorphous (LDA) ice, through supercooled and ambient water, and up to 401 C and 1730 bar, supercritical water. This linearity, from-163 to «400 C, arises because the proton motions are correlated over hydrogen-bonded distances which are determined by the SCL. Moreover, the longest acoustic phonon wavelength, namely, that of the TA or shear mode, which occurs near «55 cm-1, 1· 2 is also completely limited by the SCL. Hence, the proton (OH stretching) and center-of-mass (TA phonon) correlations both arise from, and are restricted in distance by, the size of the hydrogen-bonded aggregates or patches. Theinclusion of LDA ice in the linear relationship also suggests a possible continuity of states from amorphous ice to supercooled water, whereas the high-temperature, supercritical limit is attained when most of the hydrogen bonding is disrupted.