Dear all,
I would like to try out adding Grimme's dispersion correction to my calculation. From the manual and the list archive I understand that this can be done, however, some points are unclear to me. The parameters need to be defined in the MM.Potentials block, and if I am not mistaken, this needs to be done for each pair wise interaction between atom types. For my system containing 7 different atoms, this seems to be quite tedious. Is there a more straight forward way of doing this? Certainly I could restrict the number to only include nearest neighbours, but this is difficult to decide a priory. So, there would be a large number of pairs that would need to be considered here. Nonetheless, if I should do it this way how would I translate between different units. It appears that the original Grimme paper reports these parameters in Jnm^(6)mol^(-1) which differs from SIESTA standard units (I stumbled upon this discussion in the archive, however, I couldn't find A conclusive answer. Unfortunately I also seem to be unable to recover the post from the archive, despite some time spent searching). My last question addresses the 2 parameters MM.Grimme.D and MM.Grimme.S6. The latter is by default set to 1.66 for a DZP basis, however, For which functional is this the default. Can this value be ised straight away with PBE? Where does this value come from? Likewise, can the default value for .D be used straight away? Thanks for your help.... Tobias ________________________________ Dr. Tobias Kraemer Research Associate Institute of Chemical Sciences School of Engineering & Physical Sciences Heriot-Watt University Edinburgh EH14 4AS United Kingdom * [email protected] * +44 (0)131 451 3259 ________________________________ ----- Sunday Times Scottish University of the Year 2011-2013 Top in the UK for student experience Fourth university in the UK and top in Scotland (National Student Survey 2012) We invite research leaders and ambitious early career researchers to join us in leading and driving research in key inter-disciplinary themes. Please see www.hw.ac.uk/researchleaders for further information and how to apply. Heriot-Watt University is a Scottish charity registered under charity number SC000278.
