Hi all,

I am new to CHARMM. I am trying to get a vector time series of the system dipole.However, no useful info is written in the boxdipol.dat

Here is the input:

READ .RTF AND .PRM
READ SEQUENCE AND COORDINATES
LONE PAIR FACILITY
SET PBC USING CRYSTAL

! box dipole
open read unit 32 unformatted name ../tip4p-nvt/output/dyna.dcd

traj quer unit 32
traj first 32 nunit 1 skip ?SKIP
open write unit 33 card name boxdipol.dat
echu 33

set i 1
label loop
traj read

coor dipole sele all end

write title unit 33
*

incr i by 1
if i le ?NFILE goto loop
!End the process
close unit 33

stop

It is my understanding from the output that the trajectory was read correctly and dipole moments are calculated but the information is not being written in boxdipol.dat

Here are some parts from the output:

CHARMM> traj quer unit 32

READING TRAJECTORY FROM UNIT 32
NUMBER OF COORDINATE SETS IN FILE: 500
NUMBER OF PREVIOUS DYNAMICS STEPS: 301000
FREQUENCY FOR SAVING COORDINATES: 1000
NUMBER OF STEPS FOR CREATION RUN: 500000

NUMBER OF DEGREES OF FREEDOM: 1533
NUMBER OF FIXED ATOMS: 0
THE INTEGRATION TIME STEP (PS): 0.0010
THE FILE CONTAINS CRYSTAL UNIT CELL DATA
THE FILE DOES NOT CONTAIN 4-D DATA

CHARMM> traj first 32 nunit 1 skip ?SKIP
RDCMND substituted energy or value "?SKIP" to "1000"
TRAJ: INITIATING READ OF A TRAJECTORY, OPTIONS;
FIRSTU = 32 NUNIT = 1 SKIP = 1000

CHARMM> open write unit 33 card name boxdipol.dat
VOPEN> Attempting to open::boxdipol.dat::
OPNLGU> Unit 33 opened for WRITE access to /waterbox/analysis/boxdipol.dat

CHARMM> echu 33

CHARMM> set i 1
Parameter: I <- "1"

CHARMM> label loop

CHARMM> traj read

READING TRAJECTORY FROM UNIT 32
NUMBER OF COORDINATE SETS IN FILE: 500
NUMBER OF PREVIOUS DYNAMICS STEPS: 301000
FREQUENCY FOR SAVING COORDINATES: 1000
NUMBER OF STEPS FOR CREATION RUN: 500000

TITLE> * A BOX OF 256 TIP4P WATER MOLECULES
TITLE> * 500 PS NVT DYNAMICS - PRODUCTION
TITLE> *
***** WARNING ***** BEGIN= 0 Was not specified. It has been set to: 301000

CHARMM> coor dipole sele all end
SELRPN> 1024 atoms have been selected out of 1024
THE TOTAL CHARGE OF SELECTED ATOMS IS: 0.000000
DIPOLE MOMENT ABOUT CENTER OF GEOMETRY (DEBYES) : -95.270272 13.593494 -36.363997 102.876373

CHARMM> write title unit 33
RDTITL> *
RDTITL> No title read.

CHARMM> incr i by 1
Parameter: I <- "2"

CHARMM> if i le ?NFILE goto loop
RDCMND substituted energy or value "?NFILE" to "500"
Comparing "2" and "500".
IF test evaluated as true. Performing command
CHARMM> traj read

CHARMM> coor dipole sele all end
SELRPN> 1024 atoms have been selected out of 1024
THE TOTAL CHARGE OF SELECTED ATOMS IS: 0.000000
DIPOLE MOMENT ABOUT CENTER OF GEOMETRY (DEBYES) : -111.358020 22.111115 -51.917974 124.839842

Thanks in advance for your help