Diffusion technical issues

In the present chapter, after a brief description of the notion of diffusion and the basics of diffusion NMR, we briefly survey a few technical issues concerning diffusion NMR. Readers interested in more detailed descriptions of the theory of diffusion NMR can consult the many excellent reviews published in recent years [5-7]. 

The choice of basis sets is a particularly important technical issue for this type of calculation. Specifically, the small, highly contracted basis sets such as used in Ref. [16] generally are insufficient to calculate the real parts of dielectric functions and, consequently, the energy loss functions. We started from Partridge s 16sllp set [17], contracted the seven tightest s-functions and the four tightest p-functions, removed the most diffuse s and the two most diffuse p-functions to avoid approximate linear dependencies, and added a full set of three d-functions with exponents equal to those of the... 

For now, these partnerships can certainly be judged a success in terms of the increasing number of students able to deal with interdisciplinary problems, the enhanced technical interactions among academics and industrial scientists, the diffusing of issues surrounding the incompatibility" of their respective cultures, and the renewed awareness of our interdependence in the process of innovation. 

Biologist and earth scientist. Researcher in plant physiology at the University of Vienna until 1991 (specialised in photosynthesis research, simulation of plant bio-productivity). Over 60 publications on environmental issues. 1992 invited speaker at the Alpbach Forum 1996 winner of the grand Austrian Environment Award (of Lower Austria) top-notch journalist on environmental issues admission to the "Austrian Scientific Forum for Environment Protection", board member since 2001. Director of the Chemicals Policy Division of the BMLFUW since the end of September 1997 fields of activity legislation on chemical substances at the national, European and UN levels. Scientific and technical risk assessment of substances and products, best practice diffusion for the production and application of chemical products. 

Given that most crystals grown for a particular technical application must contain a specific concentration of a particular solute in order to possess the desired properties, it is somewhat surprising that, until recently, simulations have focussed exclusively on single-component systems. In addition to the issues of structure, dynamics and thermodynamics addressed in the earlier sections, multi-component systems can exhibit a variety of interesting phenomena relating to the differences in the density (concentration) and diffusion profiles of the separate... 

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