Water trimers

Viant M R, Cruzan J D, Luoas D D, Brown M G, Liu Kand Saykaiiy R J 1997 Pseudorotation in water trimer isotopomers using terahertz iaser speotrosoopy J. Phys. Chem. 101 9032-41... 

Pugliano N and Saykally R J 1992 Measurement of quantum tunnelling between ohiral isomers of the oyolio water trimer Science 257 1936-40... 

The three-body contribution may also be modelled using a term of the form i ( AB,tAc,J Bc) = i A,B,c exp(-Q AB)exp(-/i Ac)exp(-7 Bc) where K, a, j3 and 7 are constants describing the interaction between the atoms A, B and C. Such a functional form has been used in simulations of ion-water systems, where polarisation alone does not exactly model configurations when there are two water molecules close to an ion [Lybrand and Kollman 1985]. The three-body exchange repulsion term is thus only calculated for ion-water-water trimers when the species are close together. 

Fischer, M. Wan, P. m-Quinone methides from m-hydroxy-1,1-diaryl alkenes via excited-state (formal) intramolecular proton transfer mediated by a water trimer. J. Am. Chem. Soc. 1998, 120, 2680-2681. 

Figure 12-3. Global minimum configuration of the water trimer.

Gonzales, L., Mo, O., Yanez, M., Elguerdo, J., 1996, Cooperative Effects in Water Trimers. The Performance of Density Functional Approaches , J. Mol. Struct. (Theochem), 371, 1. 

Nielsen, I. M. B., Seidl, E., Janssen, C. L., 1999, Accurate Structures and Binding Energies for Small Water Clusters The Water Trimer , J. Chem. Phys., 110, 9435. 

Fig. 2. Perspective view of the V(OH2)6 (OH2)i2 ion exhibiting D2 symmetry. The dashed lines represent the hydrogen bonds within the cyclic water trimers in the second coordination sphere. Reproduced from Ref. (3) by permission of the Royal Society of Chemistry.

E. M. Mas, R. Bukowski, and K. Szalewicz, Ab initio three body interactions for water. I. Potential and structure of water trimer. J. Chem. Phys. 118, 4386 4403 (2003). 

In Table I we report the results on water trimer and in Fig. (6) the geometry adopted (dementi at al., 1980). A more complete work on this system will be presented later. The method has been applied to compute non additive effects, AR..JJ, for a variety of conformations of the trimer. The results have been used to generate a new ab-initio potential where many body effects were incorporated (Raimondi et al., 1997). 

Figure 3. Water trimers showing three possible arrangements where two water molecules are hydrogen bonded to a third water molecule I is asymmetric while II and III are symmetric.

Figure 1-15. Structures of the global minima for the water trimer (H20)3, tetramer (H20)4, and pentamer...

Gregory JK, Clary DC (1995) Three-body effects onmolecular properties in the water trimer. J Chem Phys 103 8924-8930... 

In the case of the water trimer the situation is much more complex. An extensive study has been performed with frozen monomer geometries and under the assumption of pairwise additive potentials 20). This structure (Fig. 13) is characterized by an almost planar arrangement of the tree oxygen and the three hydrogen atoms... 

Two systematic studies based on extensive ab initio calculations of water trimer with open-chain configuration have been reported so far 72,73). in these studies some characteristic geometrical arrangements were chosen to investigate the role of... 

Early quantum mechanical calculations [105] on the water trimer showed clearly that the sequential hydrogen bonding, 1, was energetically favored over the alternative double donor, 2, or double acceptor, 3, hydrogen bonding. 

In the water trimer induction nonadditivity provides a dominant contribution, which effectively overshadows all the other terms. Its mechanism is simple. For instance, in a cyclic water trimer the multipoles of A inductively alter the multipoles at B, which, in turn, inductively alter the multipoles at C, which then alter those on A, and so on, until the self-consistency is reached. Various formulations of this simple model were implemented in the simulations since the 1970s [84-87,63,64,50]. To include the many-body induction effects of point charges interacting with a set of polarizable atomic centers the following classical electrostatics equation is solved iteratively... 

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