Table of Contents
Keywords are used to define the type of calculation to be carried out. They are specified starting on the first line of the input file and may be spread over multiple lines. If more than one line of keywords is used, all but the final one must be terminated with a “+”. The only limitation is that the total length of the keywords must not exceed 512 characters. Most keywords may be abbreviated and the acceptable abbreviations are found in the description of each keyword that follows.
Note that if a keyword is misspelled or a keyword is used that AMPAC™ does not recognize, AMPAC will ignore it and no error message will be generated. The top of the output file should be checked if there is any doubt about which keywords were recognized by AMPAC, as they are echoed here. Keywords specific to specialized modules are listed in the Chapters describing those modules.
Read in data, then stop. 

Do 1 SCF calculation and then stop. 

Set maximum number of atoms allowed in calculation. 

Define the charge on the system. 

Override interatomic distance check. 

Interatomic Distance Matrix will be printed. 

Do not reduce gradients in FORCE. 

Output information on your AMPAC™ license. 

Suppress output of the 

Suppress output of the 

Elemental parameter set references will not be printed. 

Suppress output of the 

Suppress output of Cartesian coordinates. 

Set number of processors to use during the calculation (if supported). 

Set the maximum number of geometry optimization cycles. 

Set verbosity of output. 

Spinrestricted HartreeFock calculation. 

Restricted openshell Hartree–Fock calculation. 

Localized MOs are produced by the SCF procedure. 

Symmetry conditions will be imposed. 

Define time limit for calculation. 

Spinunrestricted HartreeFock calculation. 

Reduce the output in the 

Optimization to proceed in Cartesian space. 
Keywords in this category affect the information contained within the AMPAC output file.
Final oneelectron matrix will be printed. 

All atomic orbital contributions to the MOs will be printed. 

Set level of AMSOL printout. 

Print only nonzero elements of final twocenter bond order matrix. 

Print heat of formation calculated in the COMPFG subroutine. 

Print list of external contributors. 

Turn on additional debug output. 

Print warnings if degenerices in HOMO. 

Final density matrix will be printed. 

Print out HF eigenvalues at every step of the SCF procedure. 

Energy will be partitioned into components. 

Final Fock matrix will be printed. 

All gradient components and the gnorm will be printed. 

Cartesian force constants are output in the inertial frame. 

Localized orbitals will be printed. 

Monitor convergence of geometry optimization. 

Overlap matrix will be printed. 

Resolve density matrix into sigma and pi bonds. 

Set verbosity of output. 

Final Hessian matrix will be printed. 

Monitor convergence in selfconsistent field procedure. 

Final UHF spin matrix will be printed. 

Print timings at various stages of the calculation. 

Selected atomic orbital contributions to the MOs will be printed. 
Keywords in this category produce special output files with unique filename extensions.
Write out data for further COSMO processing. 

Density matrix will be written to disk in ASCII format. 

Density matrix will be written to disk in binary format. 

Write out data for graphics in binary format. 

Dump out the surface points and electrostatic potential values. 

Output information for input into Sybyl. 
The AM1 Hamiltonian will be used. 

Use AM1 Hamiltonian plus D3H4 dispersion and hydorgenbond corrections. 

Use AM1 Hamiltonian plus AM1FS2 dispersion and hydorgenbond corrections. 

The MINDO3 Hamiltonian will be used. 

The MNDO Hamiltonian will be used. 

The MNDOC Hamiltonian will be used. 

The MNDO/d Hamiltonian will be used. 

The PM3 Hamiltonian will be used. 

Use PM3 Hamiltonian plus D3H4 dispersion and hydorgenbond corrections. 

The PM6 Hamiltonian will be used. 

Use PM6 Hamiltonian plus D3H4 dispersion and hydorgenbond corrections. 

The RM1 Hamiltonian will be used. 

Use RM1 Hamiltonian plus D3H4 dispersion and hydorgenbond corrections. 

The SAM1 Hamiltonian will be used. 

The SAM1 Hamiltonian, with dorbitals on I and Cl, will be used. 
Read in data, then stop. 

Do 1 SCF calculation and then stop. 

Always start SCF with a new guess density. 

Explicitly invoke quadratically convergent SCF procedure. 

Additional cycles for final convergence of wavefunction. 

SCF termination criteria computed based on specified value. 

Set limit on number of SCF iterations to specified value. 
Use BFGS method in geometry optimization. 

Derivatives will be computed numerically. 

Use DavidonFletcherPowell rather than BFGS in geometry optimization. 

Use the eigenvector following method to locate a minimum. 

Exit geometry optimizations when gradient norm falls below a specified value. 

All gradient components and the gnorm will be printed. 

Use Lindh’s method for initial guess for Hessian matrix. 

Minimize gradient using full Hessian. 

Minimize energy using full Hessian. 

Default method for geometry optimization using trust radii. 

Default method for gradient minimization using trust radii. 
Use DIIS during conjugategradient steps. 

Don’t store two electron integrals. 

Supplement the matrix form used in sparse PSOLVE with additional elements. 

Use FletcherReeves version of conjugate gradient. 

Fully converge conjugate gradient at each SCF cycle. 

Use Gershgorin method to compute bounds on the Fock matrix eigenvalues. 

Generate initial guess based on Lewis dot structure analysis. 

Avoid computation of the HOMOLUMO orbitals and gap. 

Do not use preconditioning during conjugate gradient. 

Set the convergence criteria for PSOLVE=CGDMS or QNDMS. 

Set level of output during LEWIS. 

Set the sparse matrix solver method. 

Set level of output during PSOLVE and sparse matrix operations. 

Use DIIS to improve convergence of the SCF. 

Perform sparse matrix calculation using the specified neglect threshold. 

Set level shift during CGDMS or QNDMS. 
Specify dimensions for a 2D reaction grid calculation. 

Minimum allowed step length for IRC/Path. 

Follow the intrinsic reaction coordinate. 

Follow the descending reaction path. 

Specify step size for first coordinate in reaction grid calculation. 

Specify step size for second coordinate in reaction grid calculation. 

Use the eigenvector following method to locate a transition state. 

A transition vector is provided for IRC or PATH. 

Weights for T.V. components will be provided for PATH. 
(See Chapter 8, CHN Methods.)
Define the neglect threshold for lowenergy extrema during FULLCHN jobs. 

Find transition state using CHAIN method. 

Build trial path for CHN only. 

Locate limitant transition state along CHN path. 

Define the dissociation threshold for CHN methods. 

Locate transition state(s) and intermediate point(s) along CHN path. 

Maximum number of nodes in a CHAIN/CHN calculation. 

Size of queue to store candidates in simulated annealing calculation. 

Optimize left (reactant) starting geometry. 

Optimize both the left (reactant) and right (product) starting geometries. 

Optimize right (product) starting geometry. 

Optimize both the right (product) and left (reactant) starting geometries. 
Compute nonlinear optical properties using analytic gradient. 

Use Kurtz’s method for computing nonlinear optical properties in the genuine Cartesian frame. 

Unpaired spin density on atoms will be calculated. 

Force calculation for a Cartesian frequency analysis requested. 

Compute a few lowest Hessian eigenvalues. 

Force 2point formula to compute Hessian. 

Force 4point formula to compute Hessian. 

Computes hyperfine coupling constants for a UHF calculation. 

Cartesian force constants are output in the inertial frame. 

Final force matrix written to disk. 

Use Kurtz’s method for computing nonlinear optical properties in the inertial frame. 

Compute the IR spectrum for a few lowest frequencies. 

Find molecular point groups and list tolerances. 

Use specified value as tolerance to compute molecular point group. 

Defines rotational symmetry. 

Final UHF spin matrix will be printed. 

Specify step size in numerical differentiation of Hessian. 

Set the temperature range for calculating thermodynamic properties. 

Deletes the n lowest vibrations in a THERMO calculation. 
(See Chapter 11, Configuration Interaction.)
Averaged density matrix in MO basis for the first 

System has two unpaired electrons. 

Include 

Override degeneracy check. 

Calculate charges and dipole moments for CI eigenstates. 

Specify energy gap used to determine microstate degeneracy. 

Specify the maximum number of microstates. 

Write details about the CI eigenstates to file. 

Specify the number of final CI eigenstates to be calculated and printed. 

Outputs the transition dipole information between all states. 

Write details about the CI matrix diagonalization to file. 

RHF decet state required. 

RHF doublet state required. 

Outputs data for dynamic polarizability calculations. 

First excited singlet state will be optimized. 

Require use of defined set of prototype MOs. 

Read final microstates from an ASCII file. 

All unique two electron integrals over CIactive MOs written to output file. 

Energies and AO coefficients of CIactive MOs printed to output file. 

Print information about CI microstates and transitions. 

Generates only microstates with spin = 

Maximum charge for generated microstates. 

Constrains the spin multiplicity of the primary CI eigenstate to be


RHF nonet state required. 

Expand space of single excitations in a CI calculation. 

RHF octet state required. 

Configuration Interaction. 

Override the default perturbative selection of microstates. 

Define prototype MOs. 

RHF quartet state required. 

RHF quintet state required. 

Reorder MOs. 

Propagate initial selection of microstates throughout a geometry optimization. 

Specify spin state to follow. 

Defines two sets of openshell MOs and their fractional occupancies to be used in a “halfelectron” RHF SCF calculation preceding a CI calculation. 

Specify CIactive MOs in a SCI calculation. 

Specify CIactive MOs in a SDCI calculation. 

Specify CIactive MOs in a SDTCI calculation. 

Specify energy gap used to determine eigenstate degeneracy. 

RHF singlet state required. 

RHF septet state required. 

RHF sextet state required. 

Specify value of S_{z}. 

Triplet state required. 

Indicate that the microstates to be read in are fully consistent. 
(See Chapter 10, Electrostatic Potential)
Enable use of the Connolly surface for the ESP calculation. 

Specify a different point density for the Connolly surface. 

Constrain the ESP dipole moment as predicted by AMPAC’s Coulson analysis. 

Specify the xcomponent of the dipole moment. 

Specify the ycomponent of the dipole moment. 

Specify the zcomponent of the dipole moment. 

Change the number of surfaces used in the Connolly algorithm. 

Dump out the surface points and electrostatic potential values. 

Change the base scaling factor in the Connolly treatment. 

Specify the increment between multipliers for the Connolly surface. 

Change the scaling factor when using MNDO ESP charges. 

Specify basis set to “deorthogonalize” the semiempirical density matrix. 

Specify basis set to “deorthogonalize” the semiempirical density matrix. 

Average charges which should have the same value by symmetry. 

Specify surface generation procedure of Donald Williams. 
(See Chapter 13, Simulated Annealing.)
Simulated annealing search for geometric minima. 

Define default preliminary periodic boundaries. 

Define central value of the bandpass filter. 

Define halfwidth of the bandpass filter. 

Use crude rejection scheme. 

Determine balance between energy and gnorm (MANNEAL only). 

Determine equivalency of configurations during the clustering sort. 

Define central value of the energy range. 

Simulated annealing search for extrema within an energy range. 

Use a Gaussian, rather than uniform, random number generator for geometry displacement. 

Define periodic boundaries. 

Minimize gradient using full Hessian. 

Simulated annealing search for minima within an energy range. 

All points of the Markov chains are written to channel 8. 

Define interval for producing quenching candidates at each temperature. 

Minimize energy using full Hessian. 

Define maximum value of criterion calls at a given temperature. 

Skip quenching. 

Define random number seed value. 

Activate penalty function on the molecule’s moments of inertia. 

Activate close contact penalty function. 

Activate conformational penalty function. 

Activate conformational penalty function within distinct groups. 

Define the energy window penalty coefficient. 

Specify halfwidth of the searched energy range. 

Define thermalization criterion. 

Define maximum step size in the annealing search. 

Define a lower bound for the step size (% of initial step). 

Starting “temperature” for the annealing procedure. 

Print extra debugging output. 

Specify the decay constant in the temperature. 

Permitted relative variation of a bond length from its initial value. 

Simulated annealing search for extrema within an energy range. 

End the quenching steps will full optimizations. 
(See Chapter 9, Eigenvector Following )
Define the maximum size of the trust radius. 

Define the minimum size of the trust radius. 

Define the initial trust radius. 

Activate gradient test for accepting geometry steps. 

Specify the source of the Hessian matrix. 

Choice of update method for the Hessian matrix. 

Specify eigenvector to follow during optimization. 

Specify PRFO method for geometry projection. 

Suppress updating of the trust radius at Stage 3. 

Specify minimum overlap between successive TS search vectors. 

Specify interval (in number of steps) for Hessian recalculation. 

Adjust maximum criterion for accepting geometry steps. 

Adjust minimum criterion for accepting geometry steps. 

Scale the PRFO step. 
(See Chapter 14, COSMO Solvation Model.)
Invoke the COSMO solvation model. 

Write out data for further COSMO processing. 

Specify the effective molecular radius of the desired solvent. 

Specify the dielectric constant for desired solvent. (Equivalent to EPS) 

Distance threshold for using twopoint interaction approximation. 

Specify the dielectric constant for desired solvent. (Equivalent to DIELEC) 

Specify the index of refraction of the desired solvent. (Equivalent to REFRACT) 

Specify the number of segments per atom. 

Use old MINDO3 parameters with COSMO. 

Specify the index of refraction of the desired solvent. (Equivalent to IOFR) 

Specify the molecular radius of the desired solvent. 

Specify an element’s van der Waals radius. 
(See Chapter 15, AMSOL Model Module.)
Specify alpha of the desired solvent. 

Set level of AMSOL printout. 

Specify beta of the desired solvent. 

Specify the effective molecular radius of the desired solvent. 

Specify the dielectric constant for desired solvent. (Equivalent to EPS) 

Distance threshold for using twopoint interaction approximation. 

Specify the dielectric constant for desired solvent. (Equivalent to DIELEC) 

Specify the fraction of nonhydrogenic solvent atoms that are carbon atoms contained in an aromatic ring. 

Specify the fraction of nonhydrogenic solvent atoms that are electronegative halogen atoms. 

Specify the macroscopic surface tension of the desired solvent. 

Specify the heat of formation (kcal/mol) of the solute in the gas phase. 

Specify the index of refraction of the desired solvent. (Equivalent to REFRACT) 

Polarization energy computed with gas phase solvent wavefunction. 

Specify the number of segments per atom. 

Specify the index of refraction of the desired solvent. (Equivalent to IOFR) 

Specify the molecular radius of the desired solvent. 

Request a calculation using the SM5.2 model. 

Request a calculation using the SM5.2R model. 

Request a calculation using the SM5C model. 

Request a calculation using the SM5CR model. 

Indicate which parameter set will be used in the SM5 calculation. 

Solvation trapezoidal integration shell growth factor. 

Solvation trapezoidal integration shell thickness. 

Calculate the true solvation free energy. 

Specify an element’s van der Waals radius. 
Use AM1 Hamiltonian plus D3H4 dispersion and hydorgenbond corrections. 

Use AM1 Hamiltonian plus AM1FS2 dispersion and hydorgenbond corrections. 

Use PM3 Hamiltonian plus D3H4 dispersion and hydorgenbond corrections. 

Use PM6 Hamiltonian plus D3H4 dispersion and hydorgenbond corrections. 

Use RM1 Hamiltonian plus D3H4 dispersion and hydorgenbond corrections. 
#  A  B  C  D  E  F  G  H  I  K  L  M  N  O  P  Q  R  S  T  U  V  W  X 
Read in data, then stop. 

Final oneelectron matrix will be printed. 

Do 1 SCF calculation and then stop. 
Set maximum number of atoms allowed in calculation. 

All atomic orbital contributions to the MOs will be printed. 

Specify alpha of the desired solvent. 

The AM1 Hamiltonian will be used. 

Use AM1 Hamiltonian plus D3H4 dispersion and hydorgenbond corrections. 

Use AM1 Hamiltonian plus AM1FS2 dispersion and hydorgenbond corrections. 

Set level of AMSOL printout. 

Simulated annealing search for geometric minima. 

Compute nonlinear optical properties using analytic gradient. 

Define default preliminary periodic boundaries. 

Averaged density matrix in MO basis for the first 
Specify beta of the desired solvent. 

Use BFGS method in geometry optimization. 

System has two unpaired electrons. 

Print only nonzero elements of final twocenter bond order matrix. 

Define central value of the bandpass filter. 

Define halfwidth of the bandpass filter. 

Use Kurtz’s method for computing nonlinear optical properties in the genuine Cartesian frame. 
Define the neglect threshold for lowenergy extrema during FULLCHN jobs. 

Use DIIS during conjugategradient steps. 

Find transition state using CHAIN method. 

Define the charge on the system. 

Build trial path for CHN only. 

Locate limitant transition state along CHN path. 

Include n orbitals around the HOMO in the CI manifold. 

Override degeneracy check. 

Calculate charges and dipole moments for CI eigenstates. 

Specify energy gap used to determine degeneracy. 

Specify the maximum number of microstates. 

Write details about the CI eigenstates to file. 

Specify the number of final CI eigenstates to be calculated and printed. 

Outputs the transition dipole information between all states. 

Generate output options for CODESSA™ 

Print heat of formation calculated in the COMPFG subroutine. 

Enable use of the Connolly surface for the ESP calculation. 

Print list of external contributors. 

Invoke the COSMO solvation model. 

Write out data for further COSMO processing. 

Use crude rejection scheme. 

Use old parameters for element Cu with SAM1. 
Write details about the CI matrix diagonalization to file. 

Define the maximum size of the trust radius. 

Define the minimum size of the trust radius. 

Turn on additional debug output. 

RHF decet state required. 

Print warnings if degenerices in HOMO. 

Specify the effective molecular radius of the desired solvent. 

Specify a different point density for the Connolly surface. 

Density matrix will be written to disk in ASCII format. 

Density matrix will be written to disk in binary format. 

Final density matrix will be printed. 

Derivatives will be computed numerically. 

Use DavidonFletcherPowell in geometry optimization. 

Specify the dielectric constant for desired solvent. (Equivalent to EPS) 

Constrain the ESP dipole moment as predicted by AMPAC’s Coulson analysis. 

Specify the xcomponent of the dipole moment. 

Specify the ycomponent of the dipole moment. 

Specify the zcomponent of the dipole moment. 

Don’t store two electron integrals. 

Distance threshold for using twopoint interaction approximation. 

Define the dissociation threshold for CHN methods. 

Define the initial trust radius. 

RHF doublet state required. 

Outputs data for dynamic polarizability calculations. 
Use the eigenvector following method to locate a minimum. 

Print out HF eigenvalues at every step of the SCF procedure. 

Supplement the matrix form used in sparse PSOLVE with additional elements. 

Energy will be partitioned into components. 

Specify the dielectric constant for desired solvent. (Equivalent to DIELEC) 

Invokes the electrostatic potential method for charge calculation. 

Unpaired spin density on atoms will be calculated. 

First excited singlet state will be optimized. 
Specify the fraction of nonhydrogenic solvent atoms that are carbon atoms contained in an aromatic ring. 

Determine balance between energy and gnorm (MANNEAL only). 

Specify the fraction of nonhydrogenic solvent atoms that are electronegative halogen atoms. 

Require use of defined set of prototype MOs. 

Determine equivalency of configurations during the clustering sort. 

Use FletcherReeves version of conjugate gradient. 

Final Fock matrix will be printed. 

Force calculation for a Cartesian frequency analysis requested. 

Define central value of the energy range. 

Locate transition state(s) and intermediate point(s) along CHN path. 

Fully converge conjugate gradient at each SCF cycle. 
Specify the macroscopic surface tension of the desired solvent. 

Simulated annealing search for extrema within an energy range. 

Use a Gaussian, rather than uniform, random number generator for geometry displacement. 

Override interatomic distance check. 

Use Gershgorin method to compute bounds on the Fock matrix eigenvalues. 

Activate gradient test for accepting geometry steps. 

Exit geometry optimizations when gradient norm falls below a specified value. 

All gradient components and the gnorm will be printed. 

Write out data for graphics in binary format. 

Specify dimensions for a 2D reaction grid calculation. 
Specify the source of the Hessian matrix. 

Compute a few lowest Hessian eigenvalues. 

Force 2point formula to compute Hessian. 

Force 4point formula to compute Hessian. 

Specify the heat of formation (kcal/mol) of the solute in the gas phase. 

Minimum allowed step length for IRC/Path. 

Computes hyperfine coupling constants for a UHF calculation. 
Interatomic Distance Matrix will be printed. 

Read final microstates from an ASCII file. 

Cartesian force constants are output in the inertial frame.. 

Specify the index of refraction of the desired solvent. (Equivalent to REFRACT) 

Follow the intrinsic reaction coordinate. 

Final force matrix written to disk. 

Choice of update method for the Hessian matrix. 
Do not reduce gradients in FORCE. 

Generate initial guess based on Lewis dot structure analysis. 

Compute the IR spectrum for a few lowest frequencies. 

Output information on your AMPAC™ license. 

Define periodic boundaries. 

Use Lindh’s method for initial guess for Hessian matrix. 

Localized orbitals will be printed. 

Minimize gradient using full Hessian. 
Simulated annealing search for minima within an energy range. 

All points of the Markov chains are written to channel 8. 

Energies and AO coefficients of CIactive MOs printed to output file. 

Maximum number of nodes in a CHAIN/CHN calculation. 

Size of queue to store candidates in simulated annealing calculation. 

Print information about CI microstates and transitions. 

Generates only microstates with spin = 

The MINDO3 Hamiltonian will be used. 

The MNDO Hamiltonian will be used. 

The MNDOC Hamiltonian will be used. 

The MNDO/d Hamiltonian will be used. 

Specify eigenvector to follow during optimization. 

Find molecular point groups and list tolerances. 

Use specified value as tolerance to compute molecular point group. 

Maximum charge for generated microstates 

Perform a pseudoMulliken population analysis. 
Perform natrual bond orbital (NBO) analysis. 

No special correction terms will be used with the PM6 Hamiltonian. 

Define interval for producing quenching candidates at each temperature. 

Constrains the spin multiplicity of the primary CI eigenstate to be 

Always start SCF with a new guess density. 

Minimize energy using full Hessian. 

Define maximum value of criterion calls at a given temperature. 

Suppress output of the 

Avoid computation of the HOMOLUMO orbitals and gap. 

RHF nonet state required. 

Specify PRFO method for geometry projection. 

Suppress output of the 

Polarization energy computed with gas phase solvent wavefunction. 

Do not use preconditioning during conjugate gradient. 

Skip quenching. 

Elemental parameter set references will not be printed. 

Suppress updating of the trust radius at Stage 3. 

Suppress output of the 

Suppress output of Cartesian coordinates. 

Set number of processors to use during the calculation (if supported). 

Define random number seed value. 

Specify the number of segments per atom. 

Change the number of surfaces used in the Connolly algorithm. 
Expand space of single excitations in a CI calculation. 

RHF octet state required. 

Use old parameters for COSMO with MINDO3. 

Initial density matrix read from binary file. 

Initial density matrix read from ASCII file. 

Specify minimum overlap between successive TS search vectors. 

Configuration Interaction. 

Optimize left (reactant) starting geometry. 

Optimize both the left (reactant) and right (product) starting geometries. 

Optimize right (product) starting geometry. 

Optimize both the right (product) and left (reactant) starting geometries. 

Set the maximum number of geometry optimization cycles. 

Monitor convergence of geometry optimization. 

Don't reorient the input geomtry. 

Overlap matrix will be printed. 
Follow the descending reaction path. 

Set the convergence criteria for PSOLVE=CGDMS or QNDMS. 

Activate close contact penalty function. 

Activate conformational penalty function. 

Activate conformational penalty function within distinct groups. 

Activate penalty function on the molecule’s moments of inertia. 

Override the default perturbative selection of microstates. 

Resolve density matrix into sigma and pi bonds. 

The PM3 Hamiltonian will be used. 

Use PM3 Hamiltonian plus D3H4 dispersion and hydorgenbond corrections. 

The PM6 Hamiltonian will be used. 

Use PM6 Hamiltonian plus D3H4 dispersion and hydorgenbond corrections. 

Dump out the surface points and electrostatic potential values. 

Define the energy window penalty coefficient. 

Set verbosity of output. 

Final Hessian matrix will be printed. 

Define prototype MOs. 

Set level of output during LEWIS. 

Set the sparse matrix solver method. 

Set level of output during PSOLVE and other sparse matrix operations. 
Explicitly invoke quadratically convergent SCF procedure. 

RHF quartet state required. 

RHF quintet state required. 
Specify interval (in number of steps) for Hessian recalculation. 

Reorder MOs. 

Define the solvent’s refractive index. 

Calculation will be restarted using results from disk. 

Spinrestricted HartreeFock calculation. 

Propagate initial selection of microstates throughout a geometry optimization. 

The RM1 Hamiltonian will be used. 

Use RM1 Hamiltonian plus D3H4 dispersion and hydorgenbond corrections. 

Adjust maximum criterion for accepting geometry steps. 

Adjust minimum criterion for accepting geometry steps. 

Restricted openshell Hartree–Fock calculation. 

Specify spin state to follow. 

Defines rotational symmetry. 

Scale the PRFO step. 

Define the solvent’s molecular radius. 
The SAM1 Hamiltonian will be used. 

The SAM1 Hamiltonian, with dorbitals on I and Cl will be used. 

Change the base scaling factor in the Connolly treatment. 

Additional cycles for final convergence of wavefunction. 

Defines two sets of openshell MOs and their fractional occupancies to be used in a “halfelectron” RHF SCF calculation preceding a CI calculation. 

SCF termination criteria computed based on specified value. 

Use DIIS to improve convergence of the SCF. 

Localized MOs are produced by the SCF procedure. 

Set limit on number of SCF iterations to specified value. 

Monitor convergence in selfconsistent field procedure. 

Specify CIactive MOs in a SCI calculation. 

Specify the increment between multipliers for the Connolly surface. 

Specify CIactive MOs in a SDCI calculation. 

Specify CIactive MOs in a SDTCI calculation. 

Specify energy gap used to determine eigenstate degeneracy. 

RHF septet state required. 

RHF sextet state required. 

Show semiempirical method parameters for each element. 

RHF singlet state required. 

Change the scaling factor when using MNDO ESP charges. 

Request a calculation using the SM5.2 model. 

Request a calculation using the SM5.2R model. 

Request a calculation using the SM5C model. 

Request a calculation using the SM5CR model. 

Indicate which parameter set will be used in the SM5 calculation. 

Perform sparse matrix calculation using the specified neglect threshold. 

Final UHF spin matrix will be printed. 

Specify halfwidth of the searched energy range. 

Define thermalization criterion. 

Define maximum step size in the annealing search. 

Specify step size for first coordinate in reaction grid calculation. 

Specify step size for second coordinate in reaction grid calculation. 

Define a lower bound for the step size (% of initial step). 

Specify step size in numerical differentiation of Hessian. 

Specify basis set to “deorthogonalize” the semiempirical density matrix. 

Specify basis set to “deorthogonalize” the semiempirical density matrix. 

Output information for input into SYBYL®. 

Average charges which should have the same value by symmetry. 

Symmetry conditions will be imposed. 

Specify value of S_{z}. 
Define time limit for calculation. 

Starting “temperature” for the annealing procedure. 

Print extra debugging output. 

Solvation trapezoidal integration shell growth factor. 

Set the temperature range for calculating thermodynamic properties. 

Print timings at various stages of the calculation. 

Specify the decay constant in the temperature. 

Permitted relative variation of a bond length from its initial value. 

Solvation trapezoidal integration shell thickness. 

Deletes the n lowest vibrations in a THERMO calculation. 

Triplet state required. 

Calculate the true solvation free energy. 

Default method for geometry optimization using trust radii. 

Default method for gradient minimization using trust radii. 

Use the eigenvector following method to locate a transition state. 

Simulated annealing search for extrema within an energy range. 

A transition vector is provided for IRC or PATH. 
Indicate that the microstates to be read in are fully consistent. 

Specify an element’s van der Waals radius. 

Selected atomic orbital contributions to the MOs will be printed. 

Set level shift during CGDMS or QNDMS. 

Reduce the output in the 
Weights for T.V. components will be provided for PATH. 

End the quenching steps will full optimizations. 

Specify surface generation procedure of Donald Williams. 
Copyright © 19922013 Semichem, Inc. All rights reserved. 