SHADE3server: a streamlined approach to estimate H-atom anisotropic displacement parameters using periodicab initiocalculations or experimental information

Abstract

A major update of theSHADEserver (http://shade.ki.ku.dk) is presented. In addition to all of the previous options for estimating H-atom anisotropic displacement parameters (ADPs) that were offered bySHADE2, the newest version offers two new methods. The first method combines the original translation–libration–screw analysis with input from periodicab initiocalculations. The second method allows the user to input experimental information from spectroscopic measurements or from neutron diffraction experiments on related structures and utilize this information to evaluate ADPs of H atoms. Tools are provided to set up theab initiocalculations and to derive the internal motion from the calculations. The new server was tested on a range of compounds where neutron diffraction data were available. In most cases, the results are significantly better than previous estimates, and for strong hydrogen bonds in proton sponges, theab initiocalculations become crucial.