Reorientation lifetime hydrogen bond molecules

It appears (see Refs. 13 and 14) that during cooperative fast reorientations of hydrogen atoms, occurring inside a rather stable tetrahedral-like set of oxygen atoms, some favorable configuration may arise, in which a proton attached to a water molecule jumps to form another H-bond. From this viewpoint the lifetime... 

In Section VI we study in detail two fast short-lived vibration mechanisms b and c, which concern item 2. The dielectric response to the elastic rotational vibrations of hydrogen-bonded (HB) polar molecules and to translational vibrations of charges, formed on these molecules, is revealed in terms of two interrelated Lorentz lines. A proper force constant corresponds to each line. The effect of these constants on the spectra of the complex susceptibility is considered. The dielectric response of the H-bonded molecules to elastic vibrations is shown to arise in the far IR region. Namely, the translational band (T-band) at the frequency v about 200 cm-1 is caused by vibration of charges, while the neighboring V-band at v about 150 cm-1 arises due to elastic rigid-dipole reorientations. In the case of water these bands overlap, and in the case of ice they are resolved due to longer vibration lifetime. 

Infrared adsorption frequencies and line broadening (X5,1 6) have been interpreted to show that water is bound 0 downwards to the HO M. The lifetime, and population, of aggregates and hydration sheaths is strongly affected by the rotational freedom of the water molecules. In bulk water this is restricted by hydrogen bond breaking. In adsorbed layers the interaction with the adsorbate dominates reorientation for all molecules within six to ten molecular dieurneters. 

Some ions, such as Li+, Na+, Mg " ", and Ca +, have AGf, > 0 and tj > tw and were called positively hydrated . For some other ions K+, Cs+, Cr, Br , and I , ACLh < 0 and Ti < Tw and they were designated as negatively hydrated . These terms are not in general use now, however, but the relation of the residence times to the dynamic extent of hydrogen bonding in the solution is apparent. It should be noted that the residence time of a water molecule in the vicinity of another one, tw = 17 ps is considerably longer than the rotational reorientation of a water molecule, around 2-3 ps, or the mean lifetime of a hydrogen bond, 0.2-0.4 ps, see Sect. 1.1.4. 

In water the lifetime Tor of the LIB state is commensurable with a part of a picosecond and is shorter in ice. An important feature of this state is a fast reorientation (sometimes termed disorder) of hydrogen atoms inside a rather stable tetrahedral-like network of oxygen atoms. As noted above and in the Appendix I, this reorientation is cooperative, since a rotating proton, attached to a water molecule, jumps in a certain favorable configuration to form another H-bond. 

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