라벨이 first-principles calculation인 게시물 표시

Example of Hubbard U Calculation using VASP

LDAU=.TRUE. LDATYPE=2 LDAUL=-1 2 -1 2 2 LDAUU=0 5.0 0 4.64 9.0 LDAUJ=0 1.0 0 0 0 LDAUPRINT=2 Thanks, JF

Partial (projected) density of states using VASP

EMAX=upper bound (ex> 10) EMIN=lower bound (ex> -10) NEDOS=intervals (ex> 2001) LORBIT=11 Thanks, JF

How to obtain elastic constants using first-principles calculation - 2. Strain and Stress

이미지
2. Strain and Stress In order to describe the changes of displacements, strain is necessary to be defined. The configuration in the infinitesimal neighborhood around points is represented as follows: For the more for this, the Lagrangian strain tensor  can be defined. In case of stress, the Cauchy stress tensor is used to describe the state of stress in the solid. , which is the force acting outwards on a surface region . Thanks JF

How to obtain elastic constants using first-principles calculation - 1. Displacement

이미지
1. Displacement On behalf of mechanical properties, elastic constants (or elastic modulus or elastic moduli) consisting of 6 by 6 matrix are definitely important. In addition, understanding underlying theory of elasticity is indispensable to obtain by atomic scale simulation such as first-principle calculation. There are significant papers (Classic ones) as follows: BARRON, T. H. K., and KLEIN. M. L., 1963, Proc. Phys. Soc., 82, 161. "On the Strain Dependence of the Vibrational Frequency Distributions of Simple Lattices." BIRCH, F., 1947, Phys. Rev., 71, 809. "Finite Elastic Strain of Cubic Crystal." HEARMON, R. F. S., 1946, Rev. Mod. Phys., 18, 409. "The Elastic Constants of Anisotropic Materials." HUANG, K., 1950, Proc. Roy. Soc. A, 203, 178. "On the Atomic Theory of Elasticity." Among above the reported papers, Hearmon's paper is a great review (I think), which covers isotropic materials, anisotropic materials, tempera

Submit File for Iterative Calculation in Density Functional Theory (VASP) using Bash Shell

이미지
Many times we run into the situation which we should calculate iterative. In this case, this bash shell script can be used very helpfully. Here is example script. This script is that we can calculate iteratively changing the value of ISIF in INCAR file. sed "s/ISIF=${prei}/ISIF=${i}/" INCAR > temp means that find the lines with ISIF=value of prei (initial value is defined 1) and change it to ISIF=value of i ( i is changed from 1 to 7 ). So, this bash shell makes it possible to simulate with various kinds of relax conditions. $mpi_cmd -np $num_proc -hostfile $PBS_NODEFILE $lmp_cmd > vasp.log 2>&1 This command is excution command. (This is different according to your cluster environment) if [ "${prei}" -eq 7 ]; then mkdir calculatenum_${i} cp * calculatenum_${i} else prei=${i} cp CONTCAR POSCAR fi Here are the if loop that determines wheter calculated files save or not. Last calculation will be saved. The others is not sa