UT theoretical chemistry code forum

Hi, everyone,

I came across a problem while running dimer simulation. The TS was first pre-converged to 0.05 ev/A by CINEB and thereafter I switch to dimer. While it is efficient to go 0.03 eV/A, but drifted away to force as high as 0.26 ev/A.

I suspect some tweak is needed on DFNMin=0.01 and ...

got it and thanks

vasp 5.4 changes the format, and you need to specify mass

add one line anywhere in OUTCAR (at the front):
POMASS = xxx; ZVAL =
POMASS = xxx; ZVAL =
POMASS = xxx; ZVAL =
.....
before use the scripts and have fun

Hi, everyone,

I have been using nebmake.pl to prepare my files, and everything went on fine until recently. Simply put, nebmake didnt interpolate good intermediate images any more.

# image 00: POSCAR
0.6205393683339545 0.3748186251700154 0.6113134379103631 T T T
0.4407191996091184 0 ...

further update,

a contiuned neb at k221 successfully converged the ts to 0.02 ev/A....

Hi, all,

I have such a problem to examine the barrier corresponds to the barrier of flipping the Si-dimer on the famous Si(001) surface. I started by climbing neb, using 3 images, gamma point k, and the calculation successfully converged to every image below 0.02 ev/A. TS is image #2

As a next ...

thx, Graeme,

I thought about the fixed bulk atoms too in the NVE....but i still have the same problem even putting a single CO molecule....dont know where the problem is from...

a quick google guides me here, and you think that is relevant to vasp?

http://www.ncbi.nlm.nih.gov/pmc/articles ...

thanks, Graeme.

A question that sounds a bit off topic from this forum, but i am still assuming you are the right person to ask

In a MD calculation, would the overal momentum conserved during the course of the process? say, in the N, V, E conserved scheme (IBRION = 0, SMASS = -3)? I thought ...

Dear Prof. Graeme and others,

i have a thought of using the results of wonderful normal mode calculation to run a molecular dynamics simulation. I plan to excite a specific mode of a molecule adsorbed on surface.

based on my understanding, it goes as follows:

1 getting an equilibrium adsorbed ...

i am with you now, Graeme...thanks

thanks Graeme.....

when I looked at the modes at almost 0 cm-1, in addition to the expected rotation/translation, there is some stretch of bonds...is that because of the displacement in the cartesian coordinates....anyway to do it in vasp to work in the internal coordinates?

thank, Graeme,

I have a further question, how does dyn matrix generate the set of normal modes and generate the movies? Does it have something to do with the way to set up the DISPLACECAR?

In a naive thought of my case of C6H4I2, i pictured the modes as 3 trans +3 rotation +30 vibration; and in ...

we followed the instruction to calculate an adsorbed ortho diiodoebenzene, C6H4I2 on Cu...In DISPLACAR, we ask all molecular atoms to move 0.015 by x, y, z, and used the wonderful scripts to visualize these modes. I thought each mode would corresponds to the motion of a single atom in the molecules ...

I think i finally understand it now, perhaps....

Bader is talking about excess valence electron-charge. so this is a relative quantity; a positive bader charge could mean an absolute negative charge.

further update, though i dont understand

it seems to be associate with the gamma only version vasp; the regular one runs nicely. (the version we are running is 5.2.11)

my labmate had similar experience when running NEB using ibrion=3 (with gamma only version), but fine with ibrion=1(again gamma ...