LDA and GGAs cannot describe van der Waals (vdW) interactions in a physically correct way. In order to describe materials where vdW interactions are important, one needs to go beyond LDA and GGAs. To this end, one simple and popular approach is to add a Lennard-Jones type term in terms of atom-based pairwise C6=R6 summations to the existing GGA functionals. There are different ways to do this. Currently ABACUS provides three Grimme DFT-D methods, including D2, D3(0) and D3(BJ), to describe van der Waals interactions. Among them, the D3 method has been implemented in ABACUS based on the dftd3 program written by Stefan Grimme, Stephan Ehrlich and Helge Krieg.
The user can set the vdW-corrected methods in INPUT file with the parameter, vdw_method:
- none: the vdW corrections are not included
- d2: DFT-D2 method
- d3_0: DFT-D3(0) method
- d3_bj: DFT-D3(BJ) method
For example, if you want to run a DFT-D2 calculation, you should add the following keyword to the INPUT file.
vdw_method d2
By this way, ABACUS will calculate total energies and forces with DFT-D2 correction. For more parameters please refer to the list of input variables.
Below is an example using DFT + dispersion calculation:
- INPUT:
INPUT_PARAMETERS
ntype 2
ecutwfc 20
dr2 1e-06
niter 400
basis_type lcao
ks_solver genelpa
smearing gaussian
sigma 0.02
mixing_type pulay
mixing_beta 0.4
vdw_method d2
calculation scf
force 1
stress 1
- STRU:
ATOMIC_SPECIES
Sn 118.710 Sn_ONCV_PBE-1.0.upf
Te 127.603 Te_ONCV_PBE-1.0.upf
NUMERICAL_ORBITAL
Sn_pbe_9.0au_100Ry_2s2p2d
Te_pbe_9.0au_100Ry_2s2p2d
LATTICE_CONSTANT
1.89035917
LATTICE_VECTORS
4.646 0 0 #latvec1
0 4.561 0 #latvec2
0 0 16.32 #latvec3
ATOMIC_POSITIONS
Direct
Sn #label
0 #magnetism
1 #number of atoms
0.5493 0.5000000000000000 0.2 1 1 1
Te #label
0 #magnetism
1 #number of atoms
0.0000000000000000 0.0000000000000000 0.2 1 1 1
- KPT:
K_POINTS
0
Monkhorst-Pack
2 2 2 0 0 0
-
Pseudopotential and atomic basis The files (
Sn_ONCV_PBE-1.0.upf,Te_ONCV_PBE-1.0.upf,Sn_pbe_9.0au_100Ry_2s2p2d,Te_pbe_9.0au_100Ry_2s2p2d) can be found in the directory tests/tools/PP_ORB/ -
Output
*********************************************************
* *
* WELCOME TO ABACUS *
* *
* 'Atomic-orbital Based Ab-initio *
* Computation at UStc' *
* *
* Website: http:https://abacus.ustc.edu.cn/ *
* *
*********************************************************
Fri Jul 2 11:46:13 2021
MAKE THE DIR : OUT.ABACUS/
DONE(0.127021 SEC) : SETUP UNITCELL
DONE(0.128917 SEC) : INIT K-POINTS
---------------------------------------------------------
Self-consistent calculations for electrons
---------------------------------------------------------
SPIN KPOINTS PROCESSORS NBASE
1 8 1 36
---------------------------------------------------------
Use Systematically Improvable Atomic bases
---------------------------------------------------------
ELEMENT ORBITALS NBASE NATOM XC
Sn 2s2p2d-9au 18 1 PBE
Te 2s2p2d-9au 18 1 PBE
---------------------------------------------------------
Initial plane wave basis and FFT box
---------------------------------------------------------
SET NONLOCAL PSEUDOPOTENTIAL PROJECTORS
SET NONLOCAL PSEUDOPOTENTIAL PROJECTORS
DONE(4.49436 SEC) : INIT PLANEWAVE
UNIFORM GRID DIM : 30 * 30 * 90
UNIFORM GRID DIM(BIG): 15 * 15 * 45
DONE(4.49762 SEC) : INIT CHARGE
DONE(4.4993 SEC) : INIT POTENTIAL
START POTENTIAL : atomic
---------------------------------------------------------
SELF-CONSISTENT :
---------------------------------------------------------
ITER ETOT(eV) EDIFF(eV) DRHO2 TIME(s)
GE1 -4.263615e+03 0.000000e+00 1.030e-01 1.030e+00
GE2 -4.262783e+03 8.325232e-01 6.041e-02 1.010e+00
GE3 -4.262610e+03 1.722243e-01 2.263e-02 1.040e+00
GE4 -4.262486e+03 1.247259e-01 4.662e-03 1.000e+00
GE5 -4.262576e+03 -9.092446e-02 5.323e-04 9.700e-01
GE6 -4.262571e+03 5.648702e-03 1.910e-04 9.700e-01
GE7 -4.262569e+03 1.741079e-03 3.454e-05 9.600e-01
GE8 -4.262569e+03 1.839695e-04 7.188e-06 9.500e-01
GE9 -4.262569e+03 -1.606959e-05 1.728e-06 1.010e+00
GE10 -4.262569e+03 -2.716369e-05 4.516e-07 9.300e-01
><><><><><><><><><><><><><><><><><><><><><><
TOTAL-STRESS (KBAR):
><><><><><><><><><><><><><><><><><><><><><><
-2.121e+02 -8.470e-07 -2.354e-10
-8.470e-07 1.142e+02 -3.656e-13
-5.953e-10 -2.662e-13 -8.366e+01
|CLASS_NAME---------|NAME---------------|TIME(Sec)-----|CALLS----|AVG------|PER%-------
A Run_lcao lcao_line 15.77 1 16 1e+02 %
B ORB_control set_orb_tables 4.3448 1 4.3 28 %
C LCAO_Orbitals Read_Orbitals 2.327 1 2.3 15 %
C ORB_gen_tables gen_tables 2.0178 1 2 13 %
D ORB_table_phi init_Table 1.119 1 1.1 7.1 %
D ORB_table_beta init_Table_Beta 0.79881 1 0.8 5.1 %
X FFT FFT3D 0.17197 175 0.00098 1.1 %
E Potential v_of_rho 0.50032 12 0.042 3.2 %
B LOOP_ions opt_ions 11.079 1 11 70 %
C LOOP_elec solve_elec_stru 4.5258 1 4.5 29 %
D LOOP_elec before_solver 0.53419 1 0.53 3.4 %
E LCAO_Hamilt set_lcao_matrices 0.53412 1 0.53 3.4 %
G LCAO_gen_fixedH build_Nonlocal_mu 1.3624 2 0.68 8.6 %
X ORB_gen_tables snap_psibeta 2.6413 209952 1.3e-05 17 %
D LOOP_elec solver 3.9777 1 4 25 %
D ELEC_scf scf 3.9775 1 4 25 %
E ELEC_cbands_k cal_bands 1.8355 10 0.18 12 %
K Gint_k vlocal 1.635 10 0.16 10 %
G Diago_LCAO_Matrix genelpa 0.10715 40 0.0027 0.68 %
G Diago_LCAO_Matrix genelpa2 0.10148 80 0.0013 0.64 %
E Local_Orbital_Cha sum_bands 1.6351 10 0.16 10 %
F Gint_k charge 1.6077 10 0.16 10 %
E Charge mix_rho 0.10381 10 0.01 0.66 %
F Force_LCAO_k ftable_k 6.3736 1 6.4 40 %
G Force_LCAO_k cal_fvl_dphi_k 3.8463 1 3.8 24 %
G Force_LCAO_k cal_fvnl_dbeta_k 1.5456 1 1.5 9.8 %
----------------------------------------------------------------------------------------
START Time : Fri Jul 2 11:46:13 2021
FINISH Time : Fri Jul 2 11:46:29 2021
TOTAL Time : 16
SEE INFORMATION IN : OUT.ABACUS/