$SVP group (optional) The presence of this group in the input turns on use of the Surface and Simulation of Volume Polarization for Electrostatics (SS(V)PE) solvation model, or the more exact Surface and Volume Polarization for electrostatics (SVPE) model. These treat the solvent as a dielectric continuum, and are available with either an isodensity or spherical cavity around the solute. The solute may be described only by RHF, UHF, ROHF, GVB, or MCSCF wavefunctions. The energy is reported as a free energy, which includes the factor of 1/2 that accounts for the work of solvent polarization assuming linear response. Gradients are not yet available. In addition, the CMIRS (Composite Method for Implicit Representation of Solvent) model may be invoked to combine SS(V)PE with the DEFESR (Dispersion, Exchange, and Field- Extremum Short-Range) model to achieve a more complete treatment of solvation. The field-extremum contribution is designed to describe hydrogen bonding effects. The current version 1.0 of CMIRS has parameters for water solvent with isodensity cavities having contours of 0.0005, 0.001, or 0.002 au for use with the B3LYP/6-31+G*, B3LYP/G3large, HF/6-31+G*, or HF/G3large electronic structure methods. In addition, parameters are also available for cyclohexane and benzene solvents with isodensity cavities having contours of 0.0005, 0.001, or 0.002 au for use with the B3LYP/6-31+G* method. Typical use of these methods will involve a prior step to do an equivalent calculation on the given solute in the gas phase. This provides a set of orbitals that can be used as a good initial guess for the subsequent run including solvent. It also provides the gas phase energy (input as keyword EGAS) that can be subtracted from the energy in solvent to obtain the free energy of solvation. Many runs will be fine with all parameters set at their default values. The most important parameters a user may want to consider changing are: NVLPL = treatment of volume polarization 0 - SS(V)PE method, which simulates volume polarization by effectively folding in an additional surface polarization (default) N - SVPE method, which explicitly treats volume polarization with N extra layers DIELST = static dielectric constant of solvent (default = 78.39, appropriate for water) IVERT = 0 do an equilibrium calculation (default) 1 do a nonequilibrium calculation to get the final state of a vertical excitation - this requires that IRDRF=1 to read the $SVPIRF input group that was punched with IPNRF=1 in a run on the initial state - note that a meaningful result is obtained only if the initial and final states both come from the same wavefunction/basis set/ geometry/solvation model. DIELOP = optical dielectric constant of solvent - this only relevant if IVERT=1 (default 1.776, appropriate for water) EGAS = gas phase energy (optional): if given, the program will output the free energy of solvation and the change in solute internal energy due to solvation. Note that a meaningful result is obtained only if EGAS comes from the same wavefunction/basis set/ geometry as is used in the solvation calculation ISHAPE = sets the shape of the cavity surface 0 - electronic isodensity surface (default) 1 - spherical surface RHOISO = value of the electronic isodensity contour used to specify the cavity surface, in electrons/bohr**3 (relevant if ISHAPE=0; default=0.001) RADSPH = sphere radius used to specify the cavity surface. A positive value means it is given in Bohr, negative means Angstroms. (relevant if ISHAPE=1; default is half the distance between the outermost atoms plus 1.4 Angstroms) INTCAV = selects the surface integration method 0 - single center Lebedev integration (default) 1 - single center spherical polar integration, not recommended; Lebedev is far more efficient NPTLEB = number of Lebedev-type points used for single center surface integration. The default value has been found adequate to obtain the energy to within 0.1 kcal/mol for solutes the size of monosubstituted benzenes. (relevant if INTCAV=0) Valid choices are 6, 14, 26, 38, 50, 86, 110, 146, 170, 194, 302, 350, 434, 590, 770, 974, 1202, 1454, 1730, 2030, 2354, 2702, 3074, 3470, 3890, 4334, 4802, 5294, or 5810. (default=1202) NPTTHE, NPTPHI = number of (theta,phi) points used for single center surface integration. These should be multiples of 2 and 4, respectively, to provide symmetry sufficient for all Abelian point groups. (relevant if INTCAV=1; defaults = 8,16; these defaults are probably too small for all but the tiniest and simplest of solutes.) TOLCHG = a convergence criterion on the program variable named CHGDIF, which is the maximum change in any surface charge from its value in the previous iteration (default=1.0D-6). This is checked in each SCF iteration, although the actual value is not printed until final convergence is reached. The single-center surface integration approach may fail for certain highly nonspherical molecular surfaces. The program will automatically check for this and bomb out with a warning message if need be. The single-center approach succeeds only for what is called a star surface, meaning that an observer sitting at the center has an unobstructed view of the entire surface. Said another way, for a star surface any ray emanating out from the center will pass through the surface only once. Some cases of failure may be fixed by simply moving to a new center with the ITRNGR parameter described below. But some surfaces are inherently nonstar surfaces and cannot be treated with this program until more sophisticated surface integration approaches are implemented. ITRNGR = translation of cavity surface integration grid 0 - no translation (i.e., center the grid at the origin of the atomic coordinates) 1 - translate to center of nuclear mass 2 - translate to center of nucl. charge (default) 3 - translate to midpoint of outermost atoms 4 - translate to midpoint of outermost non-Hydrogen atoms 5 - translate to user-specified coordinates, in Bohr 6 - translate to user-specified coordinates, in Angstroms TRANX, TRANY, TRANZ = x,y,z coordinates of translated cavity center, relevant if ITRNGR=5 or 6. (default = 0,0,0) IROTGR = rotation of cavity surface integration grid 0 - no rotation 1 - rotate initial xyz axes of integration grid to coincide with principal moments of nuclear inertia (relevant if ITRNGR=1) 2 - rotate initial xyz axes of integration grid to coincide with principal moments of nuclear charge (relevant if ITRNGR=2; default) 3 - rotate initial xyz axes of integration grid through user-specified Euler angles as defined by Wilson, Decius, Cross ROTTHE, ROTPHI, ROTCHI = Euler angles (theta, phi, chi) in degrees for rotation of the cavity surface integration grid, relevant if IROTGR=3. (default=0,0,0) IOPPRD = choice of the system operator form. The default symmetric form is usually the most efficient, but when the number of surface points N is big it can require very large memory (to hold two N by N matrices). The nonsymmetric form requires solution of two consecutive system equations, and so is usually slower, but as trade-off requires less memory (to hold just one N by N matrix). The two forms will lead to slightly different numerical results, although tests documented in the third reference given in Further Information show that the differences are generally less than the inherent discretization error itself and so are not meaningful. 0 - symmetric form (default) 1 - nonsymmetric form * * * The CMIRS (Composite Method for Implicit Representation of Solvent) model is a combination of SS(V)PE with the DEFESR (Dispersion, Exchange, and Field-Extremum Short- Range) model. It borrows use of a grid from the DFT code, and therefore is currently implemented only for the $DFT METHOD=GRID choice in $CONTRL: note that HF calculations can be done with DFTTYP=HFX in $CONTRL. If default parameters are desired (which correspond to water solvent, an isodensity cavity with contour 0.001 au, and the B3LYP/6-31+G* electronic structure method), then only the IDEF flag needs to be set. IDEF = flag to activate DEFESR calculations 0 - DEFESR energies are not computed (default) 1 - DEFESR energies are also computed RHOSOLV = average electron density of solvent for use in the dispersion model (default=0.05 au for water) DISDMP = dispersion damping factor (default 7.0 bohr). This value has been found to be nearly optimal for all solvent/cavity/methods tested. DISLIN = dispersion linear parameter (default=0.0109369 au). It is sensitive to the solvent/cavity/method. EXCLIN = exchange linear parameter (default=0.0460402 au). It is sensitive to the solvent/cavity/method. NGSLGR = order of Gauss-Laguerre numerical integration used for the exchange term (default=6). Possible values are 1 to 25. FNNL,FPNL = field-negative and field-positive nonlinear parameters (default=3.6 and 3.6). These values have been found to be nearly optimal for all solvent/cavity/methods tested. FNLIN,FPLIN = field-negative and field-positive linear parameters (defaults=-945.810 and -17.8279 au). They are sensitive to the solvent/cavity/method. For solvents like cyclohexane and benzene that have negligible hydrogen-bonding capability they can be set to 0. SMVLE = flag to turn on an alternative (to DEFESR) semi- empirical correction for local electrostatic effects based on the electric field's normals to the surface cavity. This also adds cavitation/ dispersion/solvent structure (CDS) effects drawn from the SMD model, see SMD in $PCM. (Default=.FALSE.) * * * The remaining parameters below are rather specialized and rarely of concern. They should be changed from their default values only for good reason by a knowledgeable user. TOLCAV = convergence criterion on maximum deviation of calculated vs. requested RHOISO (relevant if ISHAPE=0; default=1.0D-10) ITRCAV = maximum number of iterations to allow before giving up in search for isodensity surface. (relevant if ISHAPE=0; default=99) NDRCAV = highest analytic density derivative to use in the search for isodensity surface. 0 - none, use finite differences (default) 1 - use analytic first derivatives LINEQ = selects the solver for the linear equations that determine the effective point charges on the cavity surface. 0 - use LU decomposition in memory if space permits, else switch to LINEQ=2 1 - use conjugate gradient iterations in memory if space permits, else use LINEQ=2 (default) 2 - use conjugate gradient iterations with the system matrix stored externally on disk. CVGLIN = convergence criterion for solving linear equations by the conjugate gradient iterative method (relevant if LINEQ=1 or 2; default = 1.0D-7) CSDIAG = a factor to multiply diagonal elements to improve the surface potential matrix, S. (default = 1.104, optimal for Lebedev integration) IRDRF = a flag to read in a set of point charges as an initial guess to the reaction field. 0 - no initial guess reaction field (default) 1 - read point charges from $SVPIRF input group. It is up to the user to be sure that the number of charges read is appropriate. IPNRF = a flag to punch the final reaction field. 0 - no punch (default) 1 - punch in format of $SVPIRF input group ========================================================== ==========================================================

generated on 7/7/2017