$TRANST group (relevant for RUNTYP=TRANSITN) (only for CITYP=GUGA or MPLEVL=2) This group controls the evaluation of the radiative transition moment, or spin orbit coupling (SOC). An SOC calculation can be based on variational CI wavefunctions, using GUGA CSFs, or based on 2nd order perturbation theory using the MCQDPT multireference perturbation theory. These are termed SO-CI and SO-MCQDPT below. The orbitals are typically obtained by MCSCF computations, and since the CI or MCQDPT wavefunctions are based on those MCSCF states, the zero-th order states are referred to below as the CAS-CI states. SOC jobs prepare a model Hamiltonian in the CAS-CI basis, and diagonalize it to produce spin- mixed states, which are linear combinations of the CAS-CI states. If scalar relativistic corrections were included in the underlying spin-free wavefunctions, it is possible either to include or to neglect similar corrections to the spin-orbit integrals, see keyword NESOC in $RELWFN. An input file to perform SO-CI will contain SCFTYP=NONE CITYP=GUGA MPLEVL=0 RUNTYP=TRANSITN while a SO-MCQDPT calculation will have SCFTYP=NONE CITYP=NONE MPLEVL=2 RUNTYP=TRANSITN The SOC job will compute a Hamiltonian matrix as the sum of spin-free terms and spin-orbit terms, H = H-sf + H-so. For SO-CI, the matrix H-sf is diagonal in the CAS-CI state basis, with the LS-coupled CAS-CI energies as the diagonal elements, and H-so contains only off-diagonal couplings between these LS states, H-sf = CAS-CI spin-free E H-so = CAS SOC Hamiltonian (e.g. HSO1, HSO2P, HSO2) For SO-MCQDPT, the additional input PARMP defines these matrices differently. For PARMP=0, the spin-free term has diagonal and off-diagonal MCQDPT perturbations: H-sf - CAS-CI spin-free E + 2nd order spin-free MCQDPT H-so - CAS SOC Hamiltonian For PARMP not equal to 0, the spin orbit operator is also included into the perturbing Hamiltonian of the MCQDPT: H-sf - CAS-CI spin-free E + 2nd order spin-free MCQDPT H-so - CAS SOC Hamiltonian + 2nd order SO-MCQDPT Pure transition moment calculations (OPERAT=DM) are presently limited to CI wavefunctions, so please use only CITYP=GUGA MPLEVL=0. The transition moments computed by SO-MCQDPT runs (see TMOMNT flag) will form the transition density for the CAS-CI zeroth order states rather than the 1st order perturbed wavefunctions. Please see REFS.DOC for additional information on what is actually a fairly complex input file to prepare. OPERAT selects the type of transition being computed. = DM calculates radiative transition moment between states of same spin, using the dipole moment operator. (default) = HSO1 one-electron Spin-Orbit Coupling (SOC) = HSO2P partial two electron and full 1e- SOC, namely core-active 2e- contributions are computed, but active-active 2e- terms are ignored. This generally captures >90% of the full HSO2 computation, but with spin-orbit matrix element time similar to the HSO1 calculation. = HSO2 one and two-electron SOC, this is the full Pauli-Breit operator. = HSO2FF one and two-electron SOC, the form factor method gives the same result as HSO2, but is more efficient in the case of small active spaces, small numbers of CAS-CI states, and large atomic basis sets. This final option applies only to SO-CI. PARMP = controls inclusion of the SOC terms in SO-MCQDPT, for OPERAT=HSO1 (default=1) or for HSO2P/HSO2 (default=3) only. 0 - no SOC terms should be included in the MCQDPT corrections at 2nd order, but they will be included in the CAS states on which the MCQDPT (i.e. up to 1st order) 1 - include the 1e- SOC perturbation in MCQDPT -1 - defined under "3", read on... 3 - full 1-electron and partial 2-electron in the form of the mean field perturbation (this is very similar to HSO2P, but in the MCQDPT2 perturbation). Only doubly occupied orbitals (NMODOC) are used for the core 2e terms. If the option is set to -1, then all core orbitals (NMOFZC+NMODOC) are used. Neither calculation includes extra diagrams including filled orbitals, so both are "partial". PARMP=3 (or -1) has almost no extra cost compared to PARMP=1, but can only be used with OPERAT=HSO2 or HSO2P. The options -1 and 3 are not rigorously justified, contrary to HOS2P for a SO-CI, as 2e integrals with 2 core indices appear in the second order in two ways. There is a mean- field addition to 1e integrals, which is included when you choose PARMP=3 or -1. But, there are separate terms from additional diagrams that are not implemented, so that there is some imbalance in including the partial 2e correction. Nevetheless, it may be better to include such "partial" partial 2e contributions than not to. Note that at first order in the energy (the CAS-CI states) the N-electron terms are treated exactly as specified by OPERAT. NFFBUF = sets buffer size for form factors in SO-MCQDPT. (applies only to OPERAT = HSO1, HSO2 or HSO2P). This is a very powerful option that speeds up SO-MCQDPT calculations by precomputing the total multiplicative factor in front of each diagram so that the latter is computed only once (this is in fact what happens in MCQDPT). It is not uncommon for this option to speed up calculations by a factor of 10. Since this option forces running the SO-CASCI part twice (due to the SO-MCQDPT Hamiltonian being non-Hermitian), it is possible that in rare cases NFFBUF=0 may perform similarly or better. The upper bound for NFFBUF is NACT**2, where NACT=NOCC-NFZC. Due to the sparseness of the coupling constants it is usually sufficient to set NFFBUF to 3*NACT. To use the older way of dynamically computing form factors and diagrams on the fly, set NFFBUF to 0. Default: 3*(NOCC-NFZC) It is advisable to tighten up the convergence criteria in the $MCQDx groups since SOC is a fairly small effect, and the spin-free energies should be accurately computed, for example THRCON=1e-8 THRGEN=1e-10. PARMP has a rather different meaning for OPERAT=HSO2FF: It refers to the difference between ket and bra's Ms, -1 do matrix elements for ms=-1 only 0 do matrix elements for ms=0 only 1 do matrix elements for ms=1 only -2 do matrix elements for all ms (0, 1, and -1), which is the default. -3 calculates form factors so they can be saved * * * next defines the orbitals and wavefunctions * * * NUMCI = For SO-CI, this parameter tells how many CI calculations to do, and therefore defines how many $DRTx groups will be read in. For SO-MCQDPT, this parameter tells how many MCQDPT calculations to do, and therefore defines how many $MCQDx groups will be read in. (default=1) IROOTS, IVEX, NSTATE, and ENGYST below will all have NUMCI values. NUMCI may not exceed 64. You may wish to define one $DRTx or $MCQDx group for each spatial symmetry representation occurring within each spin multiplicity, as the use of symmetry during these separate calculations may make the entire job run much faster. NUMVEC = the meaning is different depending on the run: a) spin-orbit CI (SO-CI), Gives the number of different MO sets. This can be either 1 or 2, but 2 can be chosen only for FORS/CASSCF or FCI wavefunctions. (default=1) If you set NUMVEC=2 and you use symmetry in any of the $DRTx groups, you may have to use STSYM in the $DRTx groups since the order of orbitals from the corresponding orbital transformation is unpredictable. b) spin-orbit perturbation (SO-MCQDPT), The option to have different MOs for different states is not implemented, so your job will have only one $VEC1 group, and IVEX will not normally be input. The absolute value of NUMVEC should be be equal to the value of NUMCI above. If NUMVEC positive, the orbitals in the $VEC1 will be used exactly as given, whereas if NUMVEC is a negative number, the orbitals will be canonicalized according to IFORB in $MCQDx. Using NUMVEC=-NUMCI and IFORB=3 in all $MCQDx to canonicalize over all states is recommended. Note that $GUESS is not read by this RUNTYP! Orbitals must be in $VEC1 and possibly $VEC2 input groups. NFZC = For SO-CI, this is equal to NFZC in each $DRTx group. When NUMVEC=2, this is also the number of identical core orbitals in the two vector sets. For SO-MCQDPT, this should be NMOFZC+NMODOC given in each of the $MCQDx groups. The default is the number of AOs given in $DATA, this is not very reasonable. NOCC = the number of occupied orbitals. For SO-CI this should be NFZC+NDOC+NALP+NAOS+NBOS+NVAL, but add the external orbitals if the CAS-CI states are CI-SD or FOCI or SOCI type instead of CAS. For SO-MCQDPT enter NUMFZC+NUMDOC+NUMACT. The default is the number of AOs given in $DATA, which is not usually correct. Note: IROOTS, NSTATE, ENGYST, IVEX contain NUMCI values. IROOTS = array containing the number of CAS-CI states to be used from each CI or MCQDPT calculation. The default is 1 for every calculation, which is probably not a correct choice for OPERAT=DM runs, but is quite reasonable for the HSO operators. The total number of states included in the SOC Hamiltonian is the summation of the NUMCI values of IROOTS times the multiplicity of each CI or MCQDPT. See also ETOL/UPPREN. NSTATE = array containing the number of CAS-CI states to be found by diagonalising the spin-free Hamiltonians. Of these, the first IROOTS(i) states will be used to find transition moments or SOC. Obviously, enter NSTATE(i) >= IROOTS(i). The default for NSTATE(i) is IROOTS(i), but might be bigger if you are curious about the additional energies, or to help the Davidson diagonalizer. NSTATE is ignored by SO-MCQDPT runs, and you must ensure that your IROOTS input corresponds to the KSTATE option in $MCQDx. ETOL = energy tolerance for CI state elimination. This applies only to SO-CI and OPERAT=HSO1,2,2P. After each CI finds NSTATE(i) CI roots for each $DRTx, the number of states kept in the run is normally IROOTS(i), but ETOL applies the further constraint that the states kept be within ETOL of the lowest energy found for any of the $DRTx. The default is 100.0 Hartree, so that IROOTS is the only limitation. UPPREN = similar to ETOL, except it is an absolute energy, instead of an energy difference. IVEX = Array of indices of $VECx groups to be used for each CI calculation. The default for NUMVEC=2 is IVEX(1)=1,2,1,1,1,1,1..., and of course for NUMVEC=1, it is IVEX(1)=1,1,1,1,1... This applies only to CITYP=GUGA jobs. ENGYST = energy values to replace the spin-free energies. This parameter applies to SO-CI only. A possible use for this is to use first or second order CI energies (FOCI or SOCI in $DRT) on the diagonal of the Hamiltonian (obtained in some earlier runs) but to use only CAS wavefunctions to evaluate off diagonal HSO matrix elements. The CAS-CI is still conducted to get CI coefs, needed to evaluate the off diagonal elements. Enter MXRT*NUMCI values as a square array, by the usual FORTRAN convention (that is, MXRT roots of $DRT1, MXRT roots of $DRT2 etc), in hartrees, with zeros added to fill each column to MXRT values. MXRT is the maximum value in the IROOTS array. (the default is the computed CAS-CI energies) See B.Schimmelpfennig, L.Maron, U.Wahlgren, C.Teichteil, H.Fagerli, O.Gropen Chem.Phys.Lett. 286, 261-266(1998). * * * the next pertain only to spin-orbit runs * * * ISTNO if given as positive values: an array of one or two state indices which govern computation of the density matrix of one state, or the transition density of two states. if given as negative values: one state-averaged density with equal weights. ISTNO(1)=5 state-specific density of state 5 ISTNO(1)=1,2 transition density between 1 and 2 ISTNO(1)=-1,-6 state-average all states 1 to 6 The default is ISTNO(1)=0,0 meaning no density. Computation of the density gives access to the full Gaussian property package, except Mulliken populations. At present, computation of the transition density does just that, without any oscillator strengths. If the computation is of SO-MCQDPT type, the density or transition density that is computed will be that for the unperturbed SO-CASCI states. DEGTOL = array of two tolerances to help define what states are considered degenerate. This is ignored except for linear molecules or atoms. The purpose is to decide what states are grouped together during the determination of simultaneous eigenstates of the spin-orbit Hamiltonian and Jz. DEGTOL(1) is in wavenumbers, and defines which spin-orbit states have the same energy. DEGTOL(2) is in units of electrons, and defines which natural orbitals are considered to be degenerate. If the Jz values in your run seem incorrect, tighten or relax the two degeneracy tolerances to get the correct groupings of the states. Default= 0.02,0.002 RSTATE = sets the zero energy level format: ndrt*1000+iroot for adiabatic state (root) 0000 sets zero energy to the lowest diabatic root default: 1001 (1st root in $DRT1 or $MCQD1) ZEFTYP specifies effective nuclear charges to use. = TRUE uses true nuclear charge of each atom, except protons are removed if an ECP basis is being used (default). = 3-21G selects values optimized for the 3-21G basis, but these are probably appropriate for any all electron basis set. Rare gases, transition metals, and Z>54 will use the true nuclear charges. = SBKJC selects a set obtained for the SBKJC ECP basis set, specifically. It may not be sensible to use these for other ECP sets. Rare gases, lanthanides, and Z>86 will use the true nuclear charges. ZEFF = an array of effective nuclear charges, overriding the charges chosen in ZEFTYP. Note that effective nuclear charges can be used for any HSO type OPERAT, but traditionally these are used mainly for HSO1 as an empirical correction to the omission of the 2e- term, or to compensate for missing core orbitals in ECP runs. ONECNT = uses a one-center approximation for SOC integrals: = 0 compute all SOC integrals without approximations = 1 compute only one-center 1e and 2e SOC integrals = 2 compute all 1e, but only one-center 2e integrals Numerical tests indicate the error of the one-center approximation (ONECNT=1) is usually on the order of a few wavenumbers for Li-Ne (a bit larger for F) and its errors appear to become negligible for anything heavier than Ne. ONECNT=1 appears to give a better balanced description than ONECNT=2. Very careful users can check how well the approximation works for their particular system by using ONECNT=0, then ONECNT=1, to compare the results. One important advantage of ONECNT=1/2 is that this removes the dependence of SOC 2e integrals upon the molecular geometry. This means the program needs to compute SOC 2e integrals only once for a given set of atoms and then they can be read by using SOC integral restart. RUNTYP=SURFACE automatically takes advantage of this fact. JZ controls the calculation of Jz eigenvalues = 0 do not perform the calculation = 1 do the calculation By default, Jz is set to 1 for molecules that are recognised as linear (this includes atoms!). Jz cannot be computed for nonlinear molecules. The matrix of Jz=Lz+Sz operator is constructed between spin-mixed states (eigenvalues of Hso). Setting Jz to 1 can enforce otherwise avoided (by symmetry) calculations of SOC matrix elements. JZ applies only to HSO1,2,2P. TMOMNT = flag to control computation of the transition dipole moment between spin-mixed wavefunctions (that is, between eigenvectors of the Pauli-Breit Hamiltonian). Applies only to HSO1,2,2P. (default is .FALSE.) SKIPDM = flag to omit(.TRUE.) or include(.FALSE.) dipole moment matrix elements during spin-orbit coupling. Usually it takes almost no addition effort to calculateexcluding some cases when the calculation of forbidden by symmetry spin-orbit coupling matrix elements may have to be performed since and are computed simultaneously. Applies only to HSO1,2,2P. Since the lack of a MCQDPT density matrix means there are no MCQDPT dipole moments at present, SO-MCQDPT jobs will compute the dipole matrix elements for the CAS-CI states only. However, the dipole moments in the spin-mixed states will be computed with the MCQDPT mixing coefficients. (default is .TRUE.) IPRHSO = controls output style for matrix elements (HSO*) =-1 do not output individual matrix elements otherwise these are accumulative: = 0 term-symbol like kind of labelling: labels contain full symmetry info (default) = 1 all states are numbered consequently within each spin multiplicity (ye olde style) = 2 output only nonzero (>=1e-4) matrix elements PRTPRM = flag to provide detailed information about the composition of the spin-mixed states in terms of adiabatic states. This flag also provides similar information about Jz (if JZ set). (default is .FALSE.) LVAL = additional angular momentum symmetry values: For the case of running an atom: LVAL is an array of the L values (L**2 = L(L+1)) for each $MCQDx/$DRTx (L=0 is S, 1 is P, etc.) For the case of running a linear molecule: LVAL is an array that gives the |Lz| values. Note that real-valued wavefunctions (e.g. Pi-x, Pi-y) have Lz and -Lz components mixed, so you should input |Lz| as 1 and 1 for both Pi-x and Pi-y. This parameter should not be given for a nonlinear polyatomic system. Default: all set to -1 (that is, do not use these additional symmetry labels. It is the user's responsibility to ensure the values' correctness. Note that for SO-MCQDPT useful options in $MCQDPT are NDIAOP and KSTATE. They enable efficient separation of atomic/linear symmetry irreps). It is acceptable to set only some values and leave others as -1, if only some groups have definite values. Note that normally Lz values are printed at the end of the log file, so its easy to double check the initial values for LVAL. For the case of atoms LVAL drastically reduces the CPU time, as it reduces a square matrix to tridiagonal form. For the case of linear molecules the savings at the spin-orbit level are somewhat less, but they are usually quite significant at the preceding spin-free MCQDPT step. MCP2E = Model Core Potential SOC 2e contributions. Note that MCP 1e contributions are handled as in case of all-electron runs because MCP orbitals contain all proper nodes). = 0 do not add the MCP 2e core-active contribution, but add any other 2e- terms asked for by OPERAT. = 1 add this contribution, but no other 2e SOC term. This is recommended, and the default. = 2 add this contribution and the 2e- contributions requested by OPERAT, for any e- which are being treated by quantum mechanics (not MCP cores). Note that for MCP2E=0 and 2, HSO2, HSO1, HSO2P values of OPERAT are supported for the explicit 2e- contributions. The recommended approach is to assume that MCP alone can capture all the 2e SOC, for this use MCP2E=1 OPERAT=HSO2P. The entire 2e- contribution is achieved with MCP2E=2 OPERAT=HSO2. If your MCP leaves out many core electrons as particles, MCP2E=2 OPERAT=HSO2P can be tested to see if it adds a sizable amount to SOC, compared to MCP2E=1 OPERAT=HSO2P). MCP2E=2 OPERAT=HSO1 is an illegal combination. MCP2E=1 OPERAT=HSO1 is illogical since the MCP 2e integrals are computed but not used anywhere. The following table explains MCP2E and gives all useful combinations: MCP2E/OPERAT 2e SOC contributions SOC 2e ints 2 HSO2 MCPcore-CIact + CIcore-CIact MCP+basis + CIact-CIact 2 HSO2P MCPcore-CIact + CIcore-CIact MCP+basis 1 HSO2P MCPcore-CIact MCP using the following orbital space definitions: MCPcore orbitals whose e- are replaced by MCP CIcore always doubly occupied CIact MOs allowed to have variable occupation * * * expert mode HSO control options * * * MODPAR = parallel options, which are independent bit options, 0=off, 1=on. Bit 1 refers only to HSO2FF, bit 2 to HSO1,2,2P. Enter a decimal value 0, 1, 2, 3 meaning binary 00, 01, 10, 11. bit 1 = 0/1 (HSO2FF) uses static/dynamic load balancing in parallel if available, otherwise use static load balancing. Dynamic algorithm is usually faster but may utilize memory less efficiently, and I/O can slow it down. Also, dynamical algorithm forces SAVDSK=.F. since its unique distribution of FFs among nodes implies no savings from precalculating form factors. bit 2 = 0/1 (HSO1,2,2P) duplicate/distribute SOC integrals in parallel. If set, 2e AO integrals and the four-index transformation are divided over nodes (distributed), and SOC MO integrals are then summed over nodes. The default is 3, meaning both bits are set on (11) PHYSRC = flag to force the size of the physical record to be equal to the size of the sorting buffers. This option can have a dramatic effect on the efficiency. Usually, setting PHYSRC=.TRUE. helps if the code complains that low memory enforces SLOWFF=.TRUE., or you set it yourself. For large active spaces and large memory (more precisely, if RECLEN is larger than the physical record size) PHYSRC=.TRUE. can slow the code down. Setting PHYSRC to .true. forces SLOWFF to be .false. See MODPAR. (default .FALSE.) (only with HSO2FF) RECLEN = specifies the size of the record on file 40, where form factors are stored. This parameter significantly affects performance. If not specified, RECLEN have to be guessed, and the guess will usually be either an overestimate or underestimate. If the former you waste disk space, if the latter the program aborts. Note that RECLEN will be different for each pair of multiplicities and you must specify the maximum for all pairs. The meaning of this number is how many non-zero form factors are present given four MO indices. You can decrease RECLEN if you are getting a message "predicted sorting buffer length is greater than needed..." Default depends on active space. (only HSO2FF) SAVDSK = flag to repeat the form factor calculation twice. This avoids wasting disk space as the actually required record size is found during the 1st run. (default=.FALSE.) (only with HSO2FF) SLOWFF = flag to choose a slower FF write-out method. By default .FALSE., but this is turned on if: 1) not enough memory for the fast way is available 2) the maximum usable memory is available, as when the buffer is as large as the maximum needed, then the "slow FF" algorythm is faster. Generally SLOWFF=.true. saves up to 50% or so of disk space. See PHYSRC. (only with HSO2FF) ACTION controls disk file DAFL30 reuse. = NORMAL calculate the form factors in this run. = SAVE calculate, and store the form factors on disk for future runs with the same active space characteristics. = READ read the form factors from disk from an earlier run which used SAVE. (default=NORMAL) (only with HSO2FF) Note that currently in order to use ACTION = SAVE or READ you should specify MS= -1, 0, or 1 * * * some control tolerances * * * NOSYM= -1 forces use of symmetry-contaminated orbitals symmetry analysis, otherwise the same as NOSYM=0 = 0 fully use symmetry = 1 do not use point group symmetry, but still use other symmetries (Hermiticity, spin). = 2 use no symmetry. Also, include all CSFs for HSO1, 2, 2P. = 3 force the code to assume the symmetry specified in $DATA is the same as in all $DRTx groups, but is otherwise identical to NOSYM=-1. This option saves CPU time and money(memory). Since the $DRT works by mapping non-Abelian groups into their highest Abelian subgroup, do not use NOSYM=3 for non-Abelian groups. SYMTOL = relative error for the matrix elements. This parameter has a great impact upon CPU time, and the default has been chosen to obtain nearly full accuracy while still getting good speedups. (default=1.0E-4) * * * the remaining parameters are not so important * * * PRTCMO = flag to control printout of the corresponding orbitals. (default is .FALSE.) HSOTOL = HSO matrix elements are considered zero if they are smaller than HSOTOL. This parameter is used only for print-out and statistics. (default=1.0E-1 cm-1) TOLZ = MO coefficient zero tolerance (as for $GUESS). (default=1.0E-8) TOLE = MO coefficient equating tolerance (as for $GUESS). (default=1.0E-5) ========================================================== * * * * * * * * * * * * * * * * * * * For information on RUNTYP=TRANSITN, see the 'further information' section * * * * * * * * * * * * * * * * * * *

generated on 7/7/2017