UT theoretical chemistry code forum

please correct me in understanding format of "modes.dat"

is tat a eigen vector matrix ?
x11 y11 z11 x12 y12 z12 ... x1natom y1natom z1natom
x21 y21 z21 x22 y22 z22 ... x2natom y2natom z2natom
. . . . . . . . . . . .
. . . . . . . . . . . .
xndof1 yndof1 zndof1 xndof2 yndof2 zndof2 ... xndofnatom ...

Since I cannot link vtstcode to vasp binay right now,
as I have nice results of IBRION=5 run (DYNMAT file, OUTCAR ..)
can you please suggest if there is any way to generate normal mode movie files (or to create modes.dat) by using vtst scripts?

Dear Dr.Graeme,
Now, after dynamical matrix calculation by modifying INCAR with
ICHAIN=1(my objective is to generate movies for each normal mode),
NSW=49(16 atoms in unitcell),
POTIM=0.0,
IBRION=3 (keeping remaining tags as it is from relaxation run)
and its a single image calculation,

while I ...

for testing here i attached OUTCAR and DISPLACECAR

error is:
Illegal division by zero at /../dymmatrix.pl line 166
line 166 is:
$matrix->[$current_displacement][$this_displacement] /= (sqrt($mass[$k]*$mass[$i]));

as I dont know perl scripting, pls anyone comment on why $mass[] is coming as zero.?
Thanks in advance.

prasad