Dear Shashi Bhusan Mishra Please read carefully the input manual:
Variable: vdw_corr Type: CHARACTER Default: 'none' See: london_s6, london_rcut, london_c6, london_rvdw, ts_vdw_econv_thr, ts_vdw_isolated, xdm_a1, xdm_a2 Description: Type of Van der Waals correction. Allowed values: 'grimme-d2', 'Grimme-D2', 'DFT-D', 'dft-d' : Semiempirical Grimme's DFT-D2. Optional variables: "london_s6", "london_rcut", "london_c6", "london_rvdw", S. Grimme, J. Comp. Chem. 27, 1787 (2006), doi:10.1002/jcc.20495 V. Barone et al., J. Comp. Chem. 30, 934 (2009), doi:10.1002/jcc.21112 'TS', 'ts', 'ts-vdw', 'ts-vdW', 'tkatchenko-scheffler' : Tkatchenko-Scheffler dispersion corrections with first-principle derived C6 coefficients (implemented in CP only). Optional variables: "ts_vdw_econv_thr", "ts_vdw_isolated" See A. Tkatchenko and M. Scheffler, PRL 102, 073005 (2009). 'XDM', 'xdm' : Exchange-hole dipole-moment model. Optional variables: "xdm_a1", "xdm_a2" A. D. Becke et al., J. Chem. Phys. 127, 154108 (2007), doi:10.1063/1.2795701 A. Otero de la Roza et al., J. Chem. Phys. 136, 174109 (2012), doi:10.1063/1.4705760 Note that non-local functionals (eg vdw-DF) are NOT specified here but in "input_dft" Therefore, if you want to use the sempiempirical Grimme's DFT-D2 correction you should *only* put vdw_corr='grimme-d2' in your input file. vdw-df refers to a *different* family of non-local ab initio functionals for the calculation of dispersion forces. Its use is *alternative* to the use of DFT-D2- HTH Giuseppe Quoting shashi bhusan mishra <mshashi...@gmail.com>: > Dear Users, > I have a confusion about adding van der waal's grimme correction > to my system. In my system I have put a adsorbate layer on top of a > substrate, the distance of separation is around 4 angstrom but when I add > vdw correction the separation decreases to 3.2 angstrom. With inclusion of > only vdW interaction, I got the separation and the adsorption energy. > However, I need to add Grimme D2 type vdW correction. Do I need to write > > > input_dft='vdw-DF' > vdw_corr = 'Grimme-D2' > > or only the correction: vdw_corr= 'Grimme-D2' without mention input dft. > I am attaching the input file. Please, let me know correction inclusion of > grimme vdW correction. This varition leads to differnt separation as well > as adsorption energy. > > > Thanks and regards, > > Shashi Bhusan Mi > shra > > Research Scholar, > > > Dept. > o > f Physics, > IIT Madras-36 > > > > > -- ******************************************************** - Article premier - Les hommes naissent et demeurent libres et égaux en droits. Les distinctions sociales ne peuvent être fondées que sur l'utilité commune - Article 2 - Le but de toute association politique est la conservation des droits naturels et imprescriptibles de l'homme. Ces droits sont la liberté, la propriété, la sûreté et la résistance à l'oppression. ******************************************************** Giuseppe Mattioli CNR - ISTITUTO DI STRUTTURA DELLA MATERIA v. Salaria Km 29,300 - C.P. 10 I 00015 - Monterotondo Stazione (RM) Tel + 39 06 90672836 - Fax +39 06 90672316 E-mail: <giuseppe.matti...@ism.cnr.it> http://www.ism.cnr.it/en/staff/giuseppe-mattioli/ ResearcherID: F-6308-2012 _______________________________________________ Pw_forum mailing list Pw_forum@pwscf.org http://pwscf.org/mailman/listinfo/pw_forum