Dear Cody,
How about putting a positional restraint (ntr=1) on ONE of your solute
atoms?
This should avoid diffusing of your solute.
--Marc
On 27 September 2015 at 21:49, Covington, Cody Lance <
cody.l.covington.vanderbilt.edu> wrote:
> Hello all
>
> During adQMMM calculations I am getting a box size error after many steps:
> ....
> NSTEP = 195200 TIME(PS) = 391.400 TEMP(K) = 297.25 PRESS =
> 141.5
> Etot = -19531.3004 EKtot = 4292.8913 EPtot =
> -23824.1917
> BOND = 3.6755 ANGLE = 19.8954 DIHED =
> -0.7372
> 1-4 NB = 4.5501 1-4 EEL = -0.1530 VDWAALS =
> 3375.4160
> EELEC = -25996.3407 EHBOND = 0.0000 RESTRAINT =
> 0.0000
> PM6ESCF= -1230.4979
> EKCMT = 2158.4788 VIRIAL = 1930.6103 VOLUME =
> 74580.0076
> Density =
> 0.9702
> Ewald error estimate: 0.2651E-01
>
> ------------------------------------------------------------------------------
>
> ****************************************************
> ERROR: QM region + cutoff larger than box dimension:
> QM-MM Cutoff = 7.0000
> Coord Lower Upper Size Radius of largest sphere inside unit
> cell
> X -16.108 9.839 25.947 20.941
> Y -13.744 10.130 23.874 20.941
> Z -27.990 27.560 55.549 20.941
> ****************************************************
> SANDER BOMB in subroutine QM_CHECK_PERIODIC<qm_mm.f>
> QM region + cutoff larger than box
> cannot continue, need larger box.
>
> I have noticed before that if part of the QM region is outside of the box
> initially, it may not image some atoms properly and give this error, so I
> centered my QM region to the center of the box before running the MD. But
> now it seems my solute has diffused to the periodic boundary during MD and
> is causing problems. Does anyone know of a way of fixing this?
>
> Thank You
> Cody Covington
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Received on Mon Sep 28 2015 - 01:30:03 PDT
