Hydrogen-bonded liquids, dynamic properties

M. S. Skaf, T. Fonseca and B. M. Ladanyi, Wave-vector-dependent dielectric relaxation in hydrogen-bonding liquids a molecular-dynamics study of methanol, J. Chem. Phys., 98 (1993) 8929-45 B. M. Ladanyi and M. S. Skaf, Wave vector-dependent dielectric relaxation of methanol-water mixtures, J. Phys. Chem., 100 (1996) 1368-80 M. S. Skaf, Molecular dynamics simulations of dielectric properties of dimethyl sulfoxide Comparison between available potentials, J. Chem. Phys., 107 (1997) 7996-8003. 

It is interesting to study the structural properties of the neat hydrogen-bonded liquid without the perturbing influence of apolar molecules in mixtures. As an example in this direction the dynamics of ethanol in the isotopic mixture are investigated. Data will be presented on ethanol-d6 samples containing 1 vol% (diluted) or 50 vol% (concentrated) of protonic ethanol (88). In contrast to the apolar CCU environment, additional H bonds between the ethanol molecules and their environment can be formed representing new species with modified properties. 

Crupi V, Majofino D, Migliardo P, Venuti V. (2002) Neutron scattering study and dynamic properties pf hydrogen-bonded liquids in mesoscopic confinement. l.The water czse. J Phys Chem B 106 10884-10894. 

The formation of covalent cross-linking in liquid-crystalline polymers is useful to lock in the molecular order in solid states, which leads to static functionality [114, 115]. For hydrogen-bonded mesogenic networks, the use of the dynamic nature of H-bonding induces dynamic properties [108, 109]. It is important to choose an appropriate method of cross-linking for the purpose of the use of network materials. 

The complexity of the physical properties of liquid water is largely determined by the presence of a three-dimensional hydrogen bond (HB) network [1]. The HB s undergo continuous transformations that occur on ultrafast timescales. The molecular vibrations are especially sensitive to the presence of the HB network. For example, the spectrum of the OH-stretch vibrational mode is substantially broadened and shifted towards lower frequencies if the OH-group is involved in the HB. Therefore, the microscopic structure and the dynamics of water are expected to manifest themselves in the IR vibrational spectrum, and, therefore, can be studied by methods of ultrafast infrared spectroscopy. It has been shown in a number of ultrafast spectroscopic experiments and computer simulations that dephasing dynamics of the OH-stretch vibrations of water molecules in the liquid phase occurs on sub-picosecond timescales [2-14],... 

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