Dear Amber Users,
I tried to set up QM/MM calculation using scc-dftb method. I downloaded the
scc-dftb parameters (3ob set) from the dftb website (www.dftb.org).
However, I got an error about Eigenvalue solver during the calculation.
Here is my input:
Minimization ENTIRE COMPLEX ---
&cntrl
imin = 1,
maxcyc = 5000,
ncyc = 2500,
ntb = 1,
ntr = 0,
cut = 8
ifqnt = 1
/
&qmmm
qmmask=":42,191,266,267,397 ",
qm_theory='DFTB',
dftb_disper=1,
dftb_chg=1,
tight_p_conv=1,
scfconv=1.0d-8,
qm_ewald=1,
qmcharge=2,
/
The QM region includes Ser, His, Water (protein), and Arg-Lys (substrate).
Here is the error:
*NSTEP ENERGY RMS GMAX NAME NUMBER *
*1 -2.6303E+05 2.5691E+00 1.4419E+02 NZ 4186 *
*BOND = 20291.2616 ANGLE = 1875.4936 DIHED = 6004.3320 *
*VDWAALS = 51206.9170 EEL = -347214.0714 HBOND = 0.0000 *
*1-4 VDW = 1303.0030 1-4 EEL = 12384.0272 RESTRAINT = 0.0000 *
*DFTBESCF= -8884.5851 *
*QMMM SCC-DFTB: *************************************************** *
*QMMM SCC-DFTB: ERROR ON EWEVGE (Eigenvalue solver). *
*QMMM SCC-DFTB: ewevge: ier = 193 inner_scf_count= 1 *
*QMMM SCC-DFTB: *************************************************** *
*QMMM SCC-DFTB: !!!! ============= WARNING ============= !!!! *
*QMMM SCC-DFTB: Convergence could not be achieved in this step. *
*QMMM SCC-DFTB: The calculation will continue, but energies and *
*QMMM SCC-DFTB: forces for this step will not be accurate. *
I also tried not to include water in the QM region, but I still got the
same error. However, if I used other QM methods (AM1, PM3 or PM6), the
calculation was fine, no error. I found in the amber-mailing list that
somebody also had the same problems as me but there were no clear solutions
to solve this problems on that time.
I hope that somebody can help me to solve this problems.
Best Regards and Thank you so much in advance,
Kanin Wichapong
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Received on Tue Jan 14 2014 - 06:30:03 PST
