Urheberrecht und Naturwissenschaften

Works in the natural sciences are provided with comparatively less copyright protection than literary works. Nevertheless, this protection is important- for scientists. However, more recently, modern methods and techniques of information and documentation, such as reprography, microfilm archives, electronic data storage and retrieval, and data transmission have questioned the justification and effectiveness, even in principle, of this protection. A more detailed analysis demonstrates that this involves not so much a crisis of copyright law as a crisis of the entire field of scientific information.     

First observation of different diffusion coefficients for two conformers in a neat liquid

 Self-diffusion coefficients were studied for the highly polar liquid N-methylformamide at pressures up to 200 MPa between the melting pressure curves and 420 K by the spin-echo method. N-Methylformamide exists as a mixture of two conformers in the neat liquid. These conformers have large differences at lower temperatures in their dynamic and structural properties. The self-diffusion coefficient of the cis-conformer being 17% lower than that of the trans-conformer at the same T and p. This is the first observation of such an effect. The experimental study is supported by Monte Carlo (MC) calculations which show that the first neighbors around a cis conformer are arranged differently than in an all trans liquid. The difference leads in the simulations to a much lower dielectric constant for the trans-cis mixture and might also explain the retardation of diffusion for the cis conformer. Received: 15 November 1999 / Accepted in revised form: 28 February 2000