problem for a large molecular system

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jjhskang
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problem for a large molecular system

#1 Post by jjhskang » Sat Jun 16, 2007 1:19 am

Hi!
I am trying to make a VASP calculation for a molecular system which consists of 199 atoms. In more detail, there are 108, 4, 8, 4, 78, and 1 atoms for C, O, N, S, H, and Ru.
The lattice parameter is very big. I use orthorhombic cell with Lx, Ly, Lz = (25, 29, 22)A. I canot reduce the size any more. In addition, I cannot use other kind of supercell.
When I tried to optimize the geometry, it did not run even one step. Namely, an electronic SCF calculation for a given geometry cannot be successfully finished. The error message I get is:

"1525-108 Error encountered while attempting to allocate a data object. The program will stop."

In the POSCAR file, I use the parameters

PREC=Nornal
ALGO=Normal
ENMAX = 400
LREAL = Auto

Since there are many hydrogen atoms, the cut-off energy cannot be no smaller than 400eV.

Could you help me find out the way to solve this probelm?

Hong Seok Kang
hsk@jj.ac.kr
Last edited by jjhskang on Sat Jun 16, 2007 1:19 am, edited 1 time in total.

tlchan

problem for a large molecular system

#2 Post by tlchan » Mon Jun 18, 2007 9:42 pm

Seems like there is not enough memory. You can use more processors to do the calculation.
Last edited by tlchan on Mon Jun 18, 2007 9:42 pm, edited 1 time in total.

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