Computer simulation contraction

Figure 7 displays the root mean square end-to-end distance as a function of the monomer density for various chain lengths. As expected, the chains are expanded in dilute solution and they contract with increasing density. The dots mark results from computer simulations [27, 49]. As is obvious from the figure, the above approach yields an excellent agreement with simulation results not only qualitatively but also quantitatively. Hence, we expect to find reliable results also for other quantities by our approach. 

I would like to thank Bogumil Jeziorski for reading and commenting on the manuscript, Edyta Malolepsza and Konrad Piszczatowski for their invaluable help at all stages of this work, and Marek Orzechowski for useful discussions on the empirical force fields and computer simulations techniques. I am also indebted to Drs. Robert Bukowski, A. Robert W. McKellar, and Konrad Patkowski for providing me with the figures, and with their results prior to publication. This work was supported by the European Research Training Network Molecular Universe (contract no. MRTN-CT-2004-512302). 

Computer simulations show general contraction and some H-bond rearrangement in vacuo... 

In the laboratory process of glass formation, an imposed temperature gradient causes heat to flow from the interior of the initially liquid system, and the liquid vitrifies—that is, loses its equilibrium properties—first at the outer surface (frequently producing a pipe in the center, where contraction at liquidlike rates continues). In the computer simulation of vitrification, it is simpler to cool the system uniformly by rescaling all the particle velocities at the same moment. This may be done either by rescaling the velocities at each time step to produce a continuous cooling or by a... 

In computer simulation studies, the supercritical region usually hosts at least two other maxima lines that are also related to anomalous properties of the liquid. These lines are the maximum density and diffusivity lines, and line, respectively (see Fig. 5). The line is defined by the set of temperatures, 2 max (p) at which the density reaches a maximum upon isobaric cooling. It follows that along this line, />( P) = - /p dp/dT)p = 0. Atr< T P),ap T, P) < 0 and the liquid expands upon isobaric cooling. Therefore, the existence of the line in the P-T plane indicates that the liquid has a density anomaly, since most liquids contract upon cooling. ... 

In order to avoid keeping in computer memory aU the 4-RDM elements, the contraction of the 4-RDM in order to get a consistent 3-RDM is simulated by another algorithm. Thus the only 4-RDM elements to be stored are the diagonal elements. All the elements are only calculated once and entered in all the places where they appear. 

The work is supported by the United States Department of Energy (Office of Basic Energy Science) through a grant under the contract number DE-FG02-05ER15723. The simulations were performed using resources of the National Center for Computational... 

Bmce Garrett received a Ph.D. in chemistry in 1977 from the University of California, Berkeley with W.H. Miller. He was a postdoctoral research specialist at the University of Minnesota with D.G. Truhlar (1977-1979) before joining the scientihc staff at Battelle Columbus Laboratories. He co-founded Chemical Dynamics Corporation, a contract research organization, where he conducted basic research from 1980 to 1989. He is currently Laboratory Fellow and Associate Director for Molecular Interactions Transformation in the Chemical Sciences Division at Pacihc Northwest National Laboratory. His hrst computational studies in 1972 involved kinetic Monte Carlo simulations with D.L. Bunker as an Undergraduate Research Assistant at the University of California, Irvine, and resulted in his hrst TACC publication in 1974. 

Figure 4.1-4. Computational fluid dynamics simulation of vapor fraction formation from a tube contraction as a function of tube length (diameter = 500pm, pressure drop = 3.45 MPa). Red areas indicate 100% vapor regions within the pipe. (This figure is available in full color at ftp //ftp.wiley.com/public/sci tech med/pharmaceutical biotech/.)...

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