Cooperativity and hydrogen bond network lifetime in liquid water

Self-Diffusion of Water at Low Temperatures and High Pressure

“…Measurements of the self-diffusion coefficient of water are important for the testing of the many proposed models of liquid water. Examples currently under scrutiny in the literature include the mixture model of Lammana et al (1995), the percolation model of Stanley and Texeira (1980), and the stability limit conjecture of Speedy (1982) (Preilmeier et al, 1987). Generally speaking, the data employed have been obtained along the saturation line rather than those obtained under high pressure, despite the fact that among the more remarkable properties of this substance are the increases in both fluidity and in the self-diffusion coefficient effected by an increase in pressure.…”

Intriguing Intermolecular Interplay in Guanine Quartet Complexes with Alkali and Alkaline Earth Cations

“…According to the authors, the term cooperativity was used by Frank and Wen in 1957 to describe the influence of formation/breakage of a single hydrogen bond on formation/breakage of other hydrogen bonds in water. Subsequently, numerous researchers investigated cooperativity and its consequences in water clusters − and bulk water. − Papers published in the last two decades on the importance of cooperativity in versatile hydrogen-bonded species signify the importance of this phenomenon. It has been recognized that it plays a crucial role in the stability of guanine aggregates (quartets, quadruplexes, ribbons) and their analogues in different environments: in the gas phase, in aqueous solutions (which mimic the biological environment), and on metal surfaces. − Besenbacher and co-workers ascribed the cooperativity of hydrogen bonds in guanine quartets to resonance-assisted hydrogen bonds, whereas Fonseca Guerra and co-workers demonstrated that it is due to donor–acceptor orbital interaction in the σ-electron system accompanied with charge separation.…”

Simultaneous photon absorption as a probe of molecular interaction and hydrogen-bond cooperativity in liquids

“…There is strong evidence [6][7][8] that in hydrogen-bonded liquids, hydrogen bonding occurs in a cooperative way: an OH group acting as an acceptor in a strong hydrogen bond in turn tends to form strong hydrogen bonds as a donor, and vice versa. It is well known that the OH-stretch frequency of a hydrogen-bonded OH group is proportional with the strength of the hydrogen bond ͑low OH-stretch frequency corresponding to short OH¯O hydrogen-bond distance 34,35 ͒.…”

“…Although it is generally believed that hydrogenbond cooperativity plays an essential role in hydrogenbonded liquids, this effect could as yet only be studied quantitatively in molecular dynamics simulations. [6][7][8] The hydrogen-bond correlation coefficient reported here, therefore, constitutes an important experimental step in the study of hydrogen-bonded liquids. As yet, no theoretical prediction is available for this number, and we hope our results will stimulate work in this direction.…”

“…It can be used to determine the vibrational interactions between neighboring molecules, and more importantly, it can be used to determine quantitatively the correlation between the strengths of neighboring hydrogen bonds. This hydrogen-bond correlation ͑or cooperativity͒ is believed to be a key property of hydrogen-bonded liquids, [6][7][8] but has as yet been difficult to investigate experimentally.…”