mndo97 (c50b1)
Combined Quantum Mechanical and Molecular Mechanics Method
Based on MNDO97 in CHARMM
by Paul Bash (pabash@nwu.edu)
Additional modifications
Kwangho Nam(nam@chem.umn.edu) and Darrin York
* Description | Description of the MNDO97 commands
* Usage | How to run MNDO97 in CHARMM
* NEWD | NEWD Command
* Installation | How to install MNDO97 in CHARMM environment
Based on MNDO97 in CHARMM
by Paul Bash (pabash@nwu.edu)
Additional modifications
Kwangho Nam(nam@chem.umn.edu) and Darrin York
* Description | Description of the MNDO97 commands
* Usage | How to run MNDO97 in CHARMM
* NEWD | NEWD Command
* Installation | How to install MNDO97 in CHARMM environment
Top
The MNDO97 QM potential is initialized with the MNDO97 command.
[SYNTAX MNDO97]
MNDO97 [REMOve] [EXGRoup] (atom selection)
[GLNK atom-selection]
[AM1|PM3|MNDO|MNDD|AMDD] [PHOT] [CHARge int]
[SWITched]
[DXLBomd] [NORDder int] [NSTEpscf int]
[D3BJ] [D3PARAM] [S6VA real] [S8VA real] [A1VA real] [A2VA real]
[H4CO] [PRED] [POHO real] [POHN real] [PNHO real] [PNHN real]
[MWHO real] [MNH4 real] [MCOO real]
[REPK real] [REPE real] [REPR real]
[NEWD int] ewald-spec [NOPMewald]
[NUQM int]
[MLAY] mlayer-spec (atom selection)
ewald-spec::= { [ KMAX integer ] } KSQMAX integer
{ KMXX integer KMXY integer KMXZ integer }
mlayer-spec::= { [IREPL int] [KHARge real] [NSTE int] [LAMB real] [QCHE OMP] }
REMOve: Classical energies within QM atoms are removed.
EXGRoup: QM/MM Electrostatics for link host groups removed.
GLNK: GHO method implementation (refer qmmm.info).
AM1: The AM1 method is to be used. (default)
PM3: The PM3 method is to be used.
MNDO: The MNDO method to be used.
MNDD: The MNDO/d method to be used.
AMDD: The AM1/d method to be used. (This method has very limited number of atoms
supported. Specifically, use in combination with PHOT keyword.)
PHOT: For the AM1/d method, PHOT use the AM1/d-PhoT method (Nam, JCTC, 2007).
Also, for Mg atom, it uses AM1 parameters.
CHARge: Total charge of QM region. (At present, it only supports RHF options.)
SWITched: Use the (group-based) switching function for the QM-MM interactions.
See below, if this option is used together with QM/MM-Ewald or QM/MM-PME
method.
DXLBomd: This uses the Niklasson JCP (2009) 130:214109 and Zheng JCT (2011) 135:044122,
in which the quess QM density is propagated using Dissipated Lagrandian MD.
The dissipation requires user to provide two variables. They are provided
using
NORDder : The maximum order to sum the dissipation terms. At present, only terms
between 3 and 9 are supported. See Niklasson JCP (2009) 130:214109.
NSTEpscf: The number of SCF cycle. Mostly, 7 or larger is safe. Also, in many cases
smaller than 7 SCF cycles provides stable MD simulations.
For details of the method, please refer Niklasson JCP (2009) 130:214109 and
Zheng JCT (2011) 135:044122.
D3BJ: Use Grimme's D3 dispersion method. The default is the two-body dispersion
correciton with Becky and Johsnson's damping function
(Grimme, JCC (2011) 32:1456)
D3PARAM: Use the user supplied D3-BJ parameters. Use the below to read user
provided parameters: S6VA, S8VA, A1VA, and A2VA
S6VA: s6 parameter. The scaling factor for the R^-6 term.
The default is 1.0 and it is advised not to change this value.
S8VA: s8 parameter. The scaling factor for the R^-8 term.
A1VA: a1 parameter. a1 and a2 are the two dampling parameters introducted by BJ.
A2VA: a2 parameter.
H4CO: Use of the H4 correction (Rezac, J Chem Theory Comput (2021) 8:141).
When it is used, it is recommended to use together with D3BJ correction.
Refer the reference for the default paramesters for AM1 and PM3 methods.
PRED: Use the user supplied H4 correction parameters:
POHO: C_OO parameter.
POHN: C_ON parameter.
PNHO: C_NO parameter.
PNHN: C_NN parameter.
MWHO: C_wat parameter.
MNH4: C_S,NHR3+ parameter.
MCOO: C_S,COO- parameter.
REPK: S_HH repulsion parameter in unit of kcal/mol.
See eq. (11) of the reference.
REPE: e_HH repulsion parameter.
REPR: r_0,HH repulsion parameter in unit of Angstrom.
NUQM: number of QM regions to specify. (default 1) This option is used to
setup multi-layered qm/mm method. see below for details.
Current implementation has a limit in choosing non-bonded options. All
atom based cutoffs methods is not fully supported for a certain boundary
conditions such as periodic boundary condition. In any case, the QM-MM
non-bond generation routine will only generate the non-bond list based
on group-group separation scheme. Especially to use any periodic boundary
conditions, use group based cutoff scheme.
The MNDO97 QM potential is initialized with the MNDO97 command.
[SYNTAX MNDO97]
MNDO97 [REMOve] [EXGRoup] (atom selection)
[GLNK atom-selection]
[AM1|PM3|MNDO|MNDD|AMDD] [PHOT] [CHARge int]
[SWITched]
[DXLBomd] [NORDder int] [NSTEpscf int]
[D3BJ] [D3PARAM] [S6VA real] [S8VA real] [A1VA real] [A2VA real]
[H4CO] [PRED] [POHO real] [POHN real] [PNHO real] [PNHN real]
[MWHO real] [MNH4 real] [MCOO real]
[REPK real] [REPE real] [REPR real]
[NEWD int] ewald-spec [NOPMewald]
[NUQM int]
[MLAY] mlayer-spec (atom selection)
ewald-spec::= { [ KMAX integer ] } KSQMAX integer
{ KMXX integer KMXY integer KMXZ integer }
mlayer-spec::= { [IREPL int] [KHARge real] [NSTE int] [LAMB real] [QCHE OMP] }
REMOve: Classical energies within QM atoms are removed.
EXGRoup: QM/MM Electrostatics for link host groups removed.
GLNK: GHO method implementation (refer qmmm.info).
AM1: The AM1 method is to be used. (default)
PM3: The PM3 method is to be used.
MNDO: The MNDO method to be used.
MNDD: The MNDO/d method to be used.
AMDD: The AM1/d method to be used. (This method has very limited number of atoms
supported. Specifically, use in combination with PHOT keyword.)
PHOT: For the AM1/d method, PHOT use the AM1/d-PhoT method (Nam, JCTC, 2007).
Also, for Mg atom, it uses AM1 parameters.
CHARge: Total charge of QM region. (At present, it only supports RHF options.)
SWITched: Use the (group-based) switching function for the QM-MM interactions.
See below, if this option is used together with QM/MM-Ewald or QM/MM-PME
method.
DXLBomd: This uses the Niklasson JCP (2009) 130:214109 and Zheng JCT (2011) 135:044122,
in which the quess QM density is propagated using Dissipated Lagrandian MD.
The dissipation requires user to provide two variables. They are provided
using
NORDder : The maximum order to sum the dissipation terms. At present, only terms
between 3 and 9 are supported. See Niklasson JCP (2009) 130:214109.
NSTEpscf: The number of SCF cycle. Mostly, 7 or larger is safe. Also, in many cases
smaller than 7 SCF cycles provides stable MD simulations.
For details of the method, please refer Niklasson JCP (2009) 130:214109 and
Zheng JCT (2011) 135:044122.
D3BJ: Use Grimme's D3 dispersion method. The default is the two-body dispersion
correciton with Becky and Johsnson's damping function
(Grimme, JCC (2011) 32:1456)
D3PARAM: Use the user supplied D3-BJ parameters. Use the below to read user
provided parameters: S6VA, S8VA, A1VA, and A2VA
S6VA: s6 parameter. The scaling factor for the R^-6 term.
The default is 1.0 and it is advised not to change this value.
S8VA: s8 parameter. The scaling factor for the R^-8 term.
A1VA: a1 parameter. a1 and a2 are the two dampling parameters introducted by BJ.
A2VA: a2 parameter.
H4CO: Use of the H4 correction (Rezac, J Chem Theory Comput (2021) 8:141).
When it is used, it is recommended to use together with D3BJ correction.
Refer the reference for the default paramesters for AM1 and PM3 methods.
PRED: Use the user supplied H4 correction parameters:
POHO: C_OO parameter.
POHN: C_ON parameter.
PNHO: C_NO parameter.
PNHN: C_NN parameter.
MWHO: C_wat parameter.
MNH4: C_S,NHR3+ parameter.
MCOO: C_S,COO- parameter.
REPK: S_HH repulsion parameter in unit of kcal/mol.
See eq. (11) of the reference.
REPE: e_HH repulsion parameter.
REPR: r_0,HH repulsion parameter in unit of Angstrom.
NUQM: number of QM regions to specify. (default 1) This option is used to
setup multi-layered qm/mm method. see below for details.
Current implementation has a limit in choosing non-bonded options. All
atom based cutoffs methods is not fully supported for a certain boundary
conditions such as periodic boundary condition. In any case, the QM-MM
non-bond generation routine will only generate the non-bond list based
on group-group separation scheme. Especially to use any periodic boundary
conditions, use group based cutoff scheme.
Top
Description of the NEWE Command
[ NEWD int ] ewald-spec [NOPMewald]
ewald-spec::= { [ KMAX integer ] } KSQMAX integer
{ KMXX integer KMXY integer KMXZ integer }
A simple Ewald sum method is implemented into the QM/MM potential. A full
description of theory is described in J. Chem. Theory. Comput. (2005) 1, 2
and Nam. JCTC (2014).
With NOPMewald, the regaular Ewald sum method is used for the QM/MM calculation.
So, this option is denoted as QM/MM-Ewald method. Without NOPMewald, if
the MM use PME method, the QM/MM part is also QM/MM-PME method. (» ewald ).
The defaults for the QM/MM-Ewald calculations are set internally and are
currently set to NEWD 1, KMAX=5, KSQMax=27, where the KMAX keyword is the
number of kvectors (or images of the primary unit cell) that will be summed
in any direction. It is the radius of the Ewald summation. For orthorombic
cells, the value of kmax may be independently specified in the x, y, and z
directions with the keywords KMXX, KMXY, and KMXZ. But, different from
regular Ewald in CHARMM, it has no limitation on the shape of box, and can be
used with PMEwald in MM part.
The KSQMax key word should be chosen between KMAX squared and 3 times
KMAX squared, and KAPPA value share the exact same number you use in Nonbond
options.
When QM/MM-Ewald or QM/MM-PME method is used together with the SWITched option.
The total energy is expressed as
E_total = Sw(r)*E_qm/mm(real space) + dE_qm/mm(periodic correction) + E_mm
E_qm/mm(real space): The regular QM/MM interaction, in which MM point charges
interact with the entire QM (electron) density.
dE_qm/mm(periodic correction)
= (1-Sw(r))*dE_qm/mm (real space part) + dE_qm/mm(reciprocal space part)
where d= Dela.
For each term, refer Nam JCTC (2005) 1, 2, and Nam JCTC (2014) 10, 4175.
When this is used with the SWITched option, the real space is switched off at the
cutoff distance, and dE_qm/mm (real space part) is turned on slowly between the
cut on and cut off distances. This makes the transition from the full QM/MM real
space potential to the dE_qm/mm (real space part) correction smoothly and thus
generate more stable MD trajectory.
Description of the NEWE Command
[ NEWD int ] ewald-spec [NOPMewald]
ewald-spec::= { [ KMAX integer ] } KSQMAX integer
{ KMXX integer KMXY integer KMXZ integer }
A simple Ewald sum method is implemented into the QM/MM potential. A full
description of theory is described in J. Chem. Theory. Comput. (2005) 1, 2
and Nam. JCTC (2014).
With NOPMewald, the regaular Ewald sum method is used for the QM/MM calculation.
So, this option is denoted as QM/MM-Ewald method. Without NOPMewald, if
the MM use PME method, the QM/MM part is also QM/MM-PME method. (» ewald ).
The defaults for the QM/MM-Ewald calculations are set internally and are
currently set to NEWD 1, KMAX=5, KSQMax=27, where the KMAX keyword is the
number of kvectors (or images of the primary unit cell) that will be summed
in any direction. It is the radius of the Ewald summation. For orthorombic
cells, the value of kmax may be independently specified in the x, y, and z
directions with the keywords KMXX, KMXY, and KMXZ. But, different from
regular Ewald in CHARMM, it has no limitation on the shape of box, and can be
used with PMEwald in MM part.
The KSQMax key word should be chosen between KMAX squared and 3 times
KMAX squared, and KAPPA value share the exact same number you use in Nonbond
options.
When QM/MM-Ewald or QM/MM-PME method is used together with the SWITched option.
The total energy is expressed as
E_total = Sw(r)*E_qm/mm(real space) + dE_qm/mm(periodic correction) + E_mm
E_qm/mm(real space): The regular QM/MM interaction, in which MM point charges
interact with the entire QM (electron) density.
dE_qm/mm(periodic correction)
= (1-Sw(r))*dE_qm/mm (real space part) + dE_qm/mm(reciprocal space part)
where d= Dela.
For each term, refer Nam JCTC (2005) 1, 2, and Nam JCTC (2014) 10, 4175.
When this is used with the SWITched option, the real space is switched off at the
cutoff distance, and dE_qm/mm (real space part) is turned on slowly between the
cut on and cut off distances. This makes the transition from the full QM/MM real
space potential to the dE_qm/mm (real space part) correction smoothly and thus
generate more stable MD trajectory.
Top
Description of the MLAY Command
[MLAY] mlayer-spec (atom selection)
ewald-spec::= { [IREPL int] [KHARge real] [NSTE int] [LAMB real] [QCHE OMP] }
A multilayer qm/mm method is implemented in the MNDO97 module with QChem
as the high-level QM package. The method is described in J. Chem. Theory Comput.
(2014) 10, 4175, to allow the multiple time step qm/mm simulations.
When the multilayer qm/mm method is used, the total qm/mm energy is
E_qm/mm (total) = E_low-levl qm/mm (PBC) + lamdba * dE_corr (high-level)
where dE_corr = [ E_high-level qm/mm (cutoff) - E_low-level qm/mm (cutoff) ].
The high-level correction term, i.e., dE_corr, can also be applied via the
multiple time step (MTS) approach.
MLAYer: Specifies whether to use/turn on the multilayer qm/mm method.
IREPL: The QM region specified for the high-level QM definition. Normally,
is 2, i.e., IREPl 2 (see below for usage).
KHARge: Charge of the high-level QM region.
NSTEp: The number of MD steps to update the high-level QM/MM energy correction.
This option is effective only with velocity Verlet MD simulations. Otherwise, it is
ignored.
LAMBda: The Lambda scaling value for the dE correction. See the equation above, where
the lambda value is between 0 and 1.
QCHEm: Use the QChem package for the high-level QM/MM calculation. The OMP option tells
to use the multi-threaded parallel version. » qchem for details.
Usage:
To use the multilayer QM/MM method, users must set up the primary/low-level qm region,
followed by the setup of the high-level QM/MM region. To do this, use the following
procedure.
! first, low-level qm/mm setup. Below, nuqm "2" specifies the allocation of
! necessary qm/mm memories for 2 QM/MM setups, where the first QM region is
! set up as below.
mndo97 sele [qm-region] end [qm theory] [charge int] remove -
nuqm 2 -
[other mndo97 se-qm/mm options] ! if other options for mndo97 se-qm/mm.
! if qchem is available, high-level qm/mm setup, for the second qm/mm region.
envi qchemcnt "qchem.inp" ! qchem input options, e.g., ./data/qchem_ewald.inp
envi qcheminp "q1.inp" ! in the test directory.
envi qchemexe "qchem"
envi qchemout "q1.out"
mndo97 mlay irepl 2 kharge 1 nstep 1 sele [qm-region] end -
qchem omp
! for energy calculation
energy
! for geometry minimization
minimization
! for MD simuations, using vver; if leap-frog verlet is used, the MTS option is
! ignored.
dynamics vver ...
nose ... ! for nose-hoover thermostat using rRESPA with nstep int>1.
Description of the MLAY Command
[MLAY] mlayer-spec (atom selection)
ewald-spec::= { [IREPL int] [KHARge real] [NSTE int] [LAMB real] [QCHE OMP] }
A multilayer qm/mm method is implemented in the MNDO97 module with QChem
as the high-level QM package. The method is described in J. Chem. Theory Comput.
(2014) 10, 4175, to allow the multiple time step qm/mm simulations.
When the multilayer qm/mm method is used, the total qm/mm energy is
E_qm/mm (total) = E_low-levl qm/mm (PBC) + lamdba * dE_corr (high-level)
where dE_corr = [ E_high-level qm/mm (cutoff) - E_low-level qm/mm (cutoff) ].
The high-level correction term, i.e., dE_corr, can also be applied via the
multiple time step (MTS) approach.
MLAYer: Specifies whether to use/turn on the multilayer qm/mm method.
IREPL: The QM region specified for the high-level QM definition. Normally,
is 2, i.e., IREPl 2 (see below for usage).
KHARge: Charge of the high-level QM region.
NSTEp: The number of MD steps to update the high-level QM/MM energy correction.
This option is effective only with velocity Verlet MD simulations. Otherwise, it is
ignored.
LAMBda: The Lambda scaling value for the dE correction. See the equation above, where
the lambda value is between 0 and 1.
QCHEm: Use the QChem package for the high-level QM/MM calculation. The OMP option tells
to use the multi-threaded parallel version. » qchem for details.
Usage:
To use the multilayer QM/MM method, users must set up the primary/low-level qm region,
followed by the setup of the high-level QM/MM region. To do this, use the following
procedure.
! first, low-level qm/mm setup. Below, nuqm "2" specifies the allocation of
! necessary qm/mm memories for 2 QM/MM setups, where the first QM region is
! set up as below.
mndo97 sele [qm-region] end [qm theory] [charge int] remove -
nuqm 2 -
[other mndo97 se-qm/mm options] ! if other options for mndo97 se-qm/mm.
! if qchem is available, high-level qm/mm setup, for the second qm/mm region.
envi qchemcnt "qchem.inp" ! qchem input options, e.g., ./data/qchem_ewald.inp
envi qcheminp "q1.inp" ! in the test directory.
envi qchemexe "qchem"
envi qchemout "q1.out"
mndo97 mlay irepl 2 kharge 1 nstep 1 sele [qm-region] end -
qchem omp
! for energy calculation
energy
! for geometry minimization
minimization
! for MD simuations, using vver; if leap-frog verlet is used, the MTS option is
! ignored.
dynamics vver ...
nose ... ! for nose-hoover thermostat using rRESPA with nstep int>1.
Top
MNDO97/CHARMM interface status (February 1997)
- MNDO97, CADPAC, GAMESS and QUANTUM keywords cannot coexist in pref.dat
To compile MNDO97 with CHARMM one uses:
$ ./configure --with-mndo97 --without-colfft
$ make -C build/cmake install
The "--with-mndo97" specifies to compile and link MNDO97 with CHARMM.
MNDO97/CHARMM interface status (February 1997)
- MNDO97, CADPAC, GAMESS and QUANTUM keywords cannot coexist in pref.dat
To compile MNDO97 with CHARMM one uses:
$ ./configure --with-mndo97 --without-colfft
$ make -C build/cmake install
The "--with-mndo97" specifies to compile and link MNDO97 with CHARMM.