Messages

16

General Questions and Answers / Re: Use molecular dynamics to calculate the surface tension of argon liquid

« on: October 20, 2016, 21:00 »

Dear Julian Schneider

Thanks for your reply.
May  i know how to get local pressure, such as P_zz(z) ,P_xx(z) , and P_yy(z)? 

Best
JY

17

General Questions and Answers / Use molecular dynamics to calculate the surface tension of argon liquid

« on: October 20, 2016, 11:12 »

Dear Sir

I am wondering if it is possible to obtain surface tension (or local pressure) directly from md_trajectory file?
The local pressure can be obtained by using Eq. (7) in the reference.
http://marge.uochb.cas.cz/~jungwirt/paper74.pdf
The first term can be obtained by local temperature times local density.
However, the second term seems to be more complicated.

The attached file is to get a stable vapor liquid interface of liquid argon at 85K by using NVT Berendsen ensemble.

18

General Questions and Answers / Vibration of CO on Cu (001)

« on: September 27, 2016, 14:37 »

Hi Sir
I try to analysiz some vibration modes of a CO molecule on metallic surface.
I already got its streching mode around 2162 cm-1. by simulating an diatomic configuration.
However, once i put CO near metallic surface consiting of 4 layers.
Then use Dynamical Matrix to simulate the CO on Cu (001),
the simulation will run and then struck in somewhere.
This should be a simple example for most users. But i failed to get the simulation resilts
I attached the file, please help to check it, thanks very much.

19

General Questions and Answers / Re: lattice_const_looping struck ....

« on: September 7, 2016, 07:08 »

I am using the Latest official release: Version 2016.0 (June 21, 2016) (64bit Wins).
So where i can find 2016a1 version.
Thanks

20

General Questions and Answers / lattice_const_looping struck ....

« on: September 6, 2016, 21:57 »

Dear Sir
I want to scan the lattice to find minimum total energy of structure.
So i use the file in the tutorial to practice it , but it always struck in the calculating Kinetic matrix.
 Please check the attached files,thanks

21

General Questions and Answers / Re: supercell

« on: August 23, 2016, 08:58 »

Hi zh
for the procedure 4 .....
->Do a geometry optimization with a constraint that the coordinates of atoms in the middle two or three layers are fixed and other atoms are allowed to relax.

However, in the tutorial CO/Pd(100), when build Pd(100) surface and relax it.
the constraint is to fix the bottom two layers of the Pd(100) surface not the middle two
http://docs.quantumwise.com/tutorials/geometry_optimization/geometry_optimization.html#build-the-pd-100-surface-and-relax-it
Could you explain this constraint a little bit?
Thanks