Topics

1

General Questions and Answers / Shape memory effect calculation using DFT

« on: June 18, 2019, 13:19 »

I am trying to validate shape memory effect in NITINOL alloy using DFT calculations in Quantumwise. I started from Semi-empirical calculation, structure optimization, elastic constant calculation, molecular dynamics with NPT ensemble for reducing temperature to 10K, and then again elastic constants calculation for validation of any change in the structure.
 Problem is coming after molecular dynamics, i.e. NPT ensemble. I have done it using molecular dynamics in LAMMPS and it is working fine.
I don't know what is the problem here in quantumwise?

2

General Questions and Answers / failed to optimize polarization energy

« on: January 15, 2019, 13:45 »

i was simulating constant strain rate deformation of a AL203 structure in NVT nose hoover with default parameters, at around 5.6k picosecond just as the fracture initiates the simulation ended giving the error "The optimization of the polarization energy failed, nlopt status: -1"
i am using Tangney_AlO_2013 potential for the simulation :

what could i be doing wrong or is it due to the choise of wrong potential??

3

General Questions and Answers / Molecular Dynamics:constant strain simulation in "molecule configuration"

« on: January 10, 2019, 14:45 »

I cannot find any option to apply strain on the molecule, the pre-strain hooks in the manual works on the box boundary. please help