Questions about nebresult.pl
Posted: Fri Jun 08, 2007 5:43 am
Dear Graeme:
Here are two questions about the Climbing NEB calculation and analysis.
1)The example INCAR file given in this website show that the NEB convergence criteria take EDIFFG=-0.001, I think this value is often too small for large slab or cluster system, in my (12x8x21 supercell size) slab system, I use EDIFFG=-0.1, I wonder my setting is small enough to obtain the correct transition state.
2)My old version (4.6.28) was compiled with PGI compiler, and all things about C-NEB calculations and analysis are right. However my newest version (4.6.31) compiled with IFC compiler show some errors during the C-NEB analysis, the details are:
firstly, I finished a C-NEB calculation (8 or 10 IMAGES), then I run the vfinl.pl(this step show no error), after that I run the nebresults.pl to give out the mep.eps, although I can obtain the mep.eps file, but here is the error information:
[b][color=green]gnuplot> plot "fe.dat" u 1:2 axis x1y1 t "Max force" w lp lt 1 lw 2.4 pt 7 ps 0.9, "fe.dat" u 1:3 axis x1y2 t "Energy" w lp lt 3 lw 2.4 pt 7 ps 0.9
^
"/opt/VASP/vtstscripts/vef.gnu", line 11: no data point found in specified file[/color][/b]
and in the vaspgr directory show 8 or 10 null vaspout(1-8 or 1-10).eps files.
After careful check, I found that the OUTCAR files given by tow different VASP (PGI and IFC compiled) show some different in the end parts of the OUTCAR files.
[b]PGI-VASP given out:[/b]
[color=red] NEB: Forces: par spring, perp spring, perp real 0.023902 0.000000 0.069815
NEB: distance to prev, next image, angle between 1.263764 1.258983 132.778095
NEB: spring constants (prev,next) 5.000000 5.000000
NEB: projections on to tangent (spring, real) -0.023902 0.113190
NEB: Forces: max atom, RMS 0.048170 0.013045
FORCES: max atom, RMS 0.048170 0.013045
Quasi-Newton relaxation of ions (Broydens 2nd method)
g(Force) = 0.147E-03 g(Stress)= 0.000E+00
retain information from N= 1 steps
eigenvalues of (default step * inverse Hessian matrix)
average eigenvalue of G= 20.9148
eigenvalue spectrum of G is 20.9148[/color]
[b]IFC-VASP given out:[/b]
[color=blue] NEB: forces: par spring, perp REAL, dneb 0.005831 0.104605 0.000000
NEB: distance to prev, next image, angle between 0.519301 0.520468 157.022063
NEB: projections on to tangent (spring, REAL) 0.005831 0.348357
FORCES: max atom, RMS 0.071629 0.011939
FORCE total and by dimension 0.104767 0.071629[/color]
I think this my be the main reason for no vaspout(1-8 or 1-10).eps file in vaspgr directory and the error information.
Can you help to fix this problem?
Thks!
Here are two questions about the Climbing NEB calculation and analysis.
1)The example INCAR file given in this website show that the NEB convergence criteria take EDIFFG=-0.001, I think this value is often too small for large slab or cluster system, in my (12x8x21 supercell size) slab system, I use EDIFFG=-0.1, I wonder my setting is small enough to obtain the correct transition state.
2)My old version (4.6.28) was compiled with PGI compiler, and all things about C-NEB calculations and analysis are right. However my newest version (4.6.31) compiled with IFC compiler show some errors during the C-NEB analysis, the details are:
firstly, I finished a C-NEB calculation (8 or 10 IMAGES), then I run the vfinl.pl(this step show no error), after that I run the nebresults.pl to give out the mep.eps, although I can obtain the mep.eps file, but here is the error information:
[b][color=green]gnuplot> plot "fe.dat" u 1:2 axis x1y1 t "Max force" w lp lt 1 lw 2.4 pt 7 ps 0.9, "fe.dat" u 1:3 axis x1y2 t "Energy" w lp lt 3 lw 2.4 pt 7 ps 0.9
^
"/opt/VASP/vtstscripts/vef.gnu", line 11: no data point found in specified file[/color][/b]
and in the vaspgr directory show 8 or 10 null vaspout(1-8 or 1-10).eps files.
After careful check, I found that the OUTCAR files given by tow different VASP (PGI and IFC compiled) show some different in the end parts of the OUTCAR files.
[b]PGI-VASP given out:[/b]
[color=red] NEB: Forces: par spring, perp spring, perp real 0.023902 0.000000 0.069815
NEB: distance to prev, next image, angle between 1.263764 1.258983 132.778095
NEB: spring constants (prev,next) 5.000000 5.000000
NEB: projections on to tangent (spring, real) -0.023902 0.113190
NEB: Forces: max atom, RMS 0.048170 0.013045
FORCES: max atom, RMS 0.048170 0.013045
Quasi-Newton relaxation of ions (Broydens 2nd method)
g(Force) = 0.147E-03 g(Stress)= 0.000E+00
retain information from N= 1 steps
eigenvalues of (default step * inverse Hessian matrix)
average eigenvalue of G= 20.9148
eigenvalue spectrum of G is 20.9148[/color]
[b]IFC-VASP given out:[/b]
[color=blue] NEB: forces: par spring, perp REAL, dneb 0.005831 0.104605 0.000000
NEB: distance to prev, next image, angle between 0.519301 0.520468 157.022063
NEB: projections on to tangent (spring, REAL) 0.005831 0.348357
FORCES: max atom, RMS 0.071629 0.011939
FORCE total and by dimension 0.104767 0.071629[/color]
I think this my be the main reason for no vaspout(1-8 or 1-10).eps file in vaspgr directory and the error information.
Can you help to fix this problem?
Thks!