From: Pang, Yui Tik (
Date: Fri May 06 2022 - 10:00:10 CDT

Hi Bassam,

It looks like ffTK didnít capture the length of the lone pair bond correctly. Would you send me your psf file so I can examine the issue better?


From: <> on behalf of Bassam Haddad <>
Sent: Thursday, May 5, 2022 12:24:24 PM
To: VMD Mailing List <>
Subject: vmd-l: FFTK Parameterization of Halogenated Molecule

Hi All,

I am having trouble with the charge optimization step in the parameterization of a halogenated molecule with a negative charge.

I am using FFTK (VMD 1.9.4a57) with ORCA_5.0.3.

ORCA terminates successfully for all atoms, despite some of them not converging in the geometry optimization step, however, FFTK fails to run the optimization step even in the absence of the ORCA outputs that didn't converge.

The error seems to indicate a problem with the LP particles, though I cannot find the difference between this current run (charge = -1) and a previous run that did work (charge = 0).

The following is the output from FFTK:

vecscale: parameters must have data
vecscale: parameters must have data
    while executing
"vecscale $dist $dir"
    (body of "dict with")
    invoked from within
"dict with value {
            set xyz_h1 [lindex $coords $host1]
            set xyz_h2 [lindex $coords $host2]

            set dir [vecnorm [vecsub ..."
    (procedure "::ForceFieldToolKit::SharedFcns::LonePair::addLPCoordinate" line 7)
    invoked from within
"::ForceFieldToolKit::SharedFcns::LonePair::addLPCoordinate $molCoords"
    (procedure "::ForceFieldToolKit::ChargeOpt::optimize" line 190)
    invoked from within
    (procedure "::ForceFieldToolKit::gui::coptRunOpt" line 55)
    invoked from within
"::ForceFieldToolKit::gui::coptRunOpt "
    invoked from within
".fftk_gui.hlf.nb.chargeopt.runOpt invoke "
    invoked from within
".fftk_gui.hlf.nb.chargeopt.runOpt instate {pressed !disabled} { .fftk_gui.hlf.nb.chargeopt.runOpt state !pressed; .fftk_gui.hlf.nb.chargeopt.runOpt in..."
    (command bound to event)

I appreciate your continued support with these issues!