Determination of the molecular arrangement from neutron or X-ray reflectivity

Neutron and X-ray reflectivity are valuable for surface analysis. Since the re is no unambiguous relation between reflectivity and scattering length de nsity profile, models with more or less realistic constraints have to be as sumed. This led to a variety of fitting methods. All currently used fitting methods have in common that they give no direct information about the mole cular conformation of the investigated system. A new method ('String Fit') presented here only requires information about the chemical structure of th e molecules involved. Far the first time it is now possible to get direct i nsight into molecular structures underlying neutron or X-ray reflectivity d ata. (C) 2000 Elsevier Science B.V. All rights reserved.