下面以NH3为例，计算NEB (umbrella inversion barrier)
STEP 1
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| &control
calculation = 'relax'
prefix = 'nh3'
outdir = './outdir'
pseudo_dir = '/BIGDATA1/ac_iphy_jrsun_1/soft/QE/SSSP'
! pseudo_dir = '/home/anonymous/quantumEspresso_2019/SSSP_precision_pseudos'
etot_conv_thr = 1e-6
forc_conv_thr = 1e-5
/
&system
ibrav=1, celldm(1) =10,
nat=4, ntyp=2,
ecutwfc=50
/
&electrons
conv_thr=1e-8
/
&ions
/
ATOMIC_SPECIES
N 14.0067 N.pbe-n-radius_5.UPF
H 1.00784 H.pbe-rrkjus_psl.1.0.0.UPF
ATOMIC_POSITIONS (angstrom)
N 0.0000 0.0000 0.379 0 0 1
H 0.4380 0.8250 0.000 1 1 0
H 0.4950 -0.792 0.000 1 1 0
H -0.934 -0.033 0.000 1 1 0
K_POINTS (automatic)
1 1 1 0 0 0
|
use pw.x to relax the ions.
STEP 2
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| BEGIN
BEGIN_PATH_INPUT
&PATH
restart_mode = 'from_scratch'
string_method = 'neb',
nstep_path = 50,
ds = 1.D0,
opt_scheme = "broyden",
num_of_images = 12,
CI_scheme = "no-CI",
path_thr = 0.05D0,
/
END_PATH_INPUT
BEGIN_ENGINE_INPUT
&CONTROL
prefix = "nh3.2"
outdir = "./outdir",
pseudo_dir = '/BIGDATA1/ac_iphy_jrsun_1/soft/QE/SSSP'
! pseudo_dir = "/home/anonymous/quantumEspresso_2019/SSSP_precision_pseudos",
/
&SYSTEM
ibrav = 1,
celldm(1) = 10,
nat = 4,
ntyp = 2,
ecutwfc = 50,
/
&ELECTRONS
conv_thr = 1.D-8,
/
&IONS
/
ATOMIC_SPECIES
N 14.0067 N.pbe-n-radius_5.UPF
H 1.00784 H.pbe-rrkjus_psl.1.0.0.UPF
BEGIN_POSITIONS
FIRST_IMAGE
ATOMIC_POSITIONS (angstrom)
N 0.000000000 0.000000000 0.393388867 0 0 1
H 0.242745664 0.905006184 0.000000000 1 1 0
H 0.662743889 -0.663017048 0.000000000 1 1 0
H -0.905089034 -0.242454521 0.000000000 1 1 0
LAST_IMAGE
ATOMIC_POSITIONS (angstrom)
N 0.000000000 0.000000000 -0.393388867 0 0 1
H 0.242745664 0.905006184 0.000000000 1 1 0
H 0.662743889 -0.663017048 0.000000000 1 1 0
H -0.905089034 -0.242454521 0.000000000 1 1 0
END_POSITIONS
K_POINTS (automatic)
1 1 1 0 0 0
END_ENGINE_INPUT
END
|
Note: The first image is the structure file from relaxed output and the last image is the inverted relaxed output.
use neb.x.
Hint (This is different from other package before.)
yhrun -N 1 -n 2 /BIGDATA1/app/Quantum_Espresso/6.5-icc-18/bin/neb.x -inp nh3.2_neb.in > nh3.2_neb.out
OR change the qe.sh as
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| #!/bin/bash
export PATH=/BIGDATA1/app/Quantum_Espresso/6.5-icc-18/bin/:$PATH
yhrun -N $SLURM_NNODES -n $SLURM_NTASKS $1 -inp nh3.2_neb.in >& nh3.2_neb.out
|
and then yhbatch -N 1 -n 24 -p bigdata ./qe.sh neb.x
Then we can find activation energy (->) = 0.237019 eV in the nh3.2_neb.out, which is the inversion energy barrier.