Unveiling two deuteration effects on hydrogen-bond breaking process of water isotopomers
Unveiling two deuteration effects on hydrogen-bond breaking process of water isotopomers
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DOI：
10.1103/physrevmaterials.3.112001
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发表时间：
2019-11-27
影响因子：
3.4
通讯作者：
Matsumoto, Yoshiyasu
中科院分区：
文献类型：
--
作者：
Kato, Fumiaki;Sugimoto, Toshiki;Matsumoto, Yoshiyasu
水中氢键的量子性质体现在特殊的物理化学同位素效应中：虽然氘化通常会拉长和削弱由大分子组成的典型氢键系统的氢键，但它会拉长但加强水分子聚集体的氢键。水分子这种独特的同位素效应的起源仍有待在分子水平上阐明。通过对具有不同H/D组成的水冰的升华进行同位素选择性测量，我们解开了对水分子氢键断裂过程的两种相反的氘化效应：（1）氘化解吸水分子增加了解吸E-d所需的能量，而（2）氘化与解吸分子相邻的水分子降低了其E-d。 E-d 的增加源于解吸分子受阻旋转中的零点能量，而 (E)d 的减少是由解吸水分子氢键相互作用中涉及的分子间和分子内振动模式之间的量子非谐耦合引起的。在这些发现的基础上，我们讨论了水分子氢键与大体积氢键分子相比的特殊性质。
The quantum nature of hydrogen bonds in water manifests itself in peculiar physicochemical isotope effects: While deuteration often elongates and weakens the hydrogen bonds of typical hydrogen-bonded systems composed of bulky constituent molecules, it elongates but strengthens the hydrogen bonds of water molecular aggregates. The origin of this unique isotope effect of water molecules remains to be elucidated at the molecular level. By means of isotope-selective measurements on the sublimation of water ices with various H/D compositions, we disentangle two opposite deuteration effects on the hydrogen-bond breaking process of water molecules: (1) Deuterating a desorbing water molecule increases the energy needed for desorption E-d, while (2) deuterating water molecules neighboring a desorbing molecule reduces its E-d. The increase in E-d originates from zero-point energy in the hindered rotation of the desorbing molecule, whereas the decrease in (E)d is caused by quantum anharmonic couplings between the inter- and intramolecular vibrational modes involved in the hydrogen-bonding interactions of desorbing water molecules. On the basis of these findings, we discuss the peculiar nature of hydrogen bonds of water molecules in comparison with bulky hydrogen-bonded molecules.