氢键在低温、高压和团簇条件下的非对称弛豫动力学及水的反常物性

Understanding the anomalous behavior of hydrogen bond and water ice under regular conditions is critical to the advancement of life and medical sciences. The traditional Ice Rule of Pauling (1935) and the popular TIPnQ(n = 1~5) models are suitable for phase structure and binding energy optimization but new theoretical methods are greatly desired for unveil the physics behind the H-bond and watre ice anomalies. This probject aims to systematically investigate the asymmetric relaxation dynamics of hydrogen bond and its impact on the anomalies of water ice under the variation of pressure, temperature, and water cluster size. Our following hypotheses will be verified both computationally and experimentally: i) An H-bond shall be segmented into two parts; one is the much weaker (virtual) nonbonding electron pair ":" and the other the stronger real bonding electron pair "-"; ii) Driven by the Coulomb repulsion between the unevenly-bound electron pairs, asymmetric relaxation in length and energy will happen to the H-bond under external stimuli such as temperature, pressure, and the size of water cluster; iii) The real bond follows the regular rules of thermal expansion and the bond order-length-strength correlation; iv) the weaker nonbond is readily compressed and polarized. If either the real or the virtual bond shrinks, the other one will expand simultaneously, being independent of the applied stimuli or the structural phases. Such cooperative interaction triggers, for instances, the puzzles of the cooling and cluster-size-reduction induced volume expansion, the pressure-induced proton symmetrization and volume compression and the size-reduction-enhanced binding energy, melting point elevation, charge densification and polarization, and the frequency shift of Raman phonons of H2O under various stimuli. Confirmation of the hypotheses will result in new theoretical methods towards finding the soul of water ice and hydrogen-bond involved processes and specimens.

准确地理解氢键及水在常规条件下的反常物性对促进生命科学和药物科学的发展以及对疾病的防护和治疗意义重大。泡令的"冰(成键)规则"和目前流行的TIPnQ(n = 1-5)模型仅限于对水的晶相结构和结合能的优化，而对于水的反常物性的认知迫切需要新的理论和思维方法。此项目拟在前期工作的基础上集中研究在变温、变压、和改变水分子团簇中分子数目情况下的氢键的分段弛豫动力学行为及其与水的物性的关联。通过实验测量和理论计算验证我们所提的假说：1）氢键可分解成弱的非（虚）键电子孤对和强的实键电子对两段；2）两电子对间的库伦排斥驱动氢键的两段在外场作用下发生非对称长度和能量的弛豫；3）实键服从常规的热膨胀和低配位键弛豫规则；4）虚键易被极化和压缩；5）氢键的长度和总能决定水和冰的反常物性。从而创立新的理论和思维方法，以图破解冰之谜。

准确地理解氢键及水在常规条件下的反常物性对促进生命科学和药物科学的发展以及对疾病的防护和治疗意义重大。泡令的“冰成键规则”和目前流行的TIPnQ(n = 1-5)模型仅限于对水的晶相结构和结合能的优化，而对于水的反常物性的认知迫切需要新的理论和思维方法。我们拓展了泡令的“冰成键规则”，构建了水分子的中心四面体堆垛结构并提出了O:H-O非对称耦合双振子氢键模型。结合实验测量和理论计算证实了这一氢键模型的合理性并验证了“氧氧间的库仑作用调制着氢键双段的非对称弛豫”这一假说。以此为基础，我们应用拉格朗日方法对这一氢键模型进行了内部短程作用力的解析分析，建立了谱学实验测量值与氢键弛豫物理参量之间的定量关联；研究了变温、变压及团簇条件下氢键的弛豫动力学行为；创立了拉曼散射差谱分析技术，实现了对谱学微量信息的提取与分析。基于这些理论、计算和实验研究，澄清了浮冰、复冰、表面超固态、姆潘巴效应等冰/水奇异现象的物理机制。已建立了一套系统和完善的理论和分析方法。破解氢键之谜，在有机和无机以及有生命和无生命领域的应用价值不可估量。