What Has Been Learned from Molecular Simulation

2 What has been Learned from Molecular Simulation  

Here we list some of the most significant applications of molecular simulation, as provided by Wierzchowski (Personal Communication, October 4,2006) although this list is by no means exhaustive. Since the first applications of molecular simulation to hydrates by Tse, et al. (1983a,b 1984), the tool has been widely used to interpret physical behavior. Simulation has impacted six major hydrate research areas. 

Nucleation. Understanding the phenomena of nucleation is a central concept to developing a hydrate formation model. As detailed in Chapter 3, Radhakrishnan and Trout (2002) used a new simulation technique to formulate a concept of hydrate 

Anomalous properties—thermal expansivity and thermal conductivity. Molecular simulation has been integral in evaluating physical behaviors of hydrate compared with ice, specifically a larger thermal expansivity (Tse, et al., 1987 Tanaka, et al., 1997) and a glasslike thermal conductivity (Tse, et al., 1983 1984 Inoue, et al., 1996). These properties have been explained by the coupling between the water and the guest molecules. 

In summary, the MD, MC, and LD (lattice dynamic) techniques are very powerful tools to investigate hydrate phenomena. Indeed, hydrate computer simulations may shortly outnumber hydrate experimental observations, because simulations are generally more accessible than experiments. However, such tools investigate phenomena which are on much smaller time and space dimensions than normally observed, outside of spectroscopy. Even with spectroscopy, the relevant peaks may be subject to some interpretation. As a result there may be several microscopic interpretations (based upon hundreds to thousands of molecules) of macroscopic phenomena which involve typically 1023 molecules. Such a scale-up may cause misinterpretation. 

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