25.2.25 Keywords for Module `pnoccsd`

Note that beside the keywords listed below the outcome of the pnoccsd program also depends on the settings of most thresholds that influence the integral screening (e.g. $denconv, $scfconv, $scftol). For the explanation of these keywords see Section 25.2.10.

$cbas file=auxbasis

Auxiliary basis set for RI approximation.

$freeze

Freeze orbitals in the calculation of correlation and excitation energies. For details see Section 25.2.4.

$printlevel 1

Print level. The default value is 1.

$tmpdir /work/thisjob

Specify a directory for large intermediate files (typically three-index coulomb integrals and similar intermediates), which is different from the directory where the program is started.

$maxcor n unit reference

The data group $maxcor adjusts the maximum size of core memory which will be allocated during the pnoccsd run. $maxcor has a large influence on computation times. It is recommended to set $maxcor to ca. 75–85% of the available physical core memory. For further details see subsection 25.2.3.

$laplace

conv = 1

Only needed for the (T) perturbative triples correction; for other methods only for test purposes. It sets the accuracy for the numerical Laplace-transformation to $10^{-\text{conv}}$ used for the (T) correction and the iterative OSV generation. For the (T0) correction and methods without triples his threshold is only used for the approximate doubles amplitudes from which the OSVs are computed when the iterative algorithm is enabled. The default value is $10^{-1}$ for the OSV generation and $10^{-2}$ for the (T) correction. If specified the input value will currently be used in both cases.

$pnoccsd

mp2
localize ibo
osvmode  paos
paos     tnos
mxrdim   800 
tolpno=   1.00E-7
tolosv=   1.00E-9
tolri=    1.21E-3
tolpair=  4.64E-6
opnos on 
tolcapno= 1.00E-9   3.16E-8
tolosc=   1.00E-10  3.15E-9
tolopno=  1.00E-9
toloso=   1.00E-10
conv    = 7
oconv   = 3
lindep  = 12
maxiter = 25
mxdiis  = 10
maxred  = 100
scs  cos=1.2d0   css=0.3333d0
sos

mp2: specifies the ab initio model (method). The current release version is restriced to MP2, CCSD, CCSD(T0) and CCSD(T). MP2 is the default model.
localize: specifies the localization method; possible choices are boys for Foster-Boys, pm for Pipek-Mezey, ibo for intrinsic bond orbitals (IBOs) and none for canonical (deprecated, only meant for testing) orbitals. Default are (since V7.3) IBOs, which are recommended if e.g. for aromatic systems the seperation of $\sigma$- and $\pi$-type orbitals is important. (Pipek-Mezey orbitals become very delocal with diffuse basis sets.)
osvmode: switch between to algorithms for the generation of OSV coefficients. Possible choices are full for an ${\cal O}({\cal N}^4)$ scaling direct diagonalization (cmp. [421]), davidson for an ${\cal O}({\cal N}^3)$ scaling iterative diagonalization (cmp. [24]) and paos for sub-${\cal O}({\cal N}^2)$ scaling implementation. paos is the default choice and recommended but is not currently compatible with gradients, excited states or explicit correlation, for which cases davidson is the default.
mxrdim: the maximal dimension of trial vectors in the iterative OSV generation (osvmode davidson). For PNO-MP2 the default is 800. The dimension is bounded by the number of active virtual orbitals and except for small systems a much smaller value as the number of virutals is sufficient. Smaller dimensions increase the performance, but than the iterative scheme might not converge and the program must be restarted with an adjusted dimension. For PNO-MP2-F12 the Default is 4000 since a larger reduced space is required to construct the OSX (cmp. [421]). Usually there is no need to touch this parameter.
tolpno: specifies the PNO truncation threshold. Default value: $10^{-7}$.
tolosv: specifies the OSV truncation threshold. If no given tolosv is set set such that the OSV truncation error is 10 times smaller than the PNO truncation error.
toltno: specifies the TNO truncation threshold. If no given toltno is set set equal to tolpno.
paos: (de)-activates PAO selection at OSV, PNO and TNO steps. Possible choices are off, osv, pno, tn0 and tno, which turn on PAO selection at the specified level and all earlier levels. If PAOs are used and no PAO selection is performed, the domains are constructed by merging the domains one level below (eg pair domains are formed by merging OSV domains). The default is tno, which activates PAO selection at every step and is recommended.
tolopao: specifies the PAO truncation threshold for OSVs, the default is linked to tolpno.
tolppao: specifies the PAO truncation threshold for PNOs, the default is linked to tolpno.
tolt0pao: specifies the PAO truncation threshold for T0-TNOs, the default is linked to toltno.
toltpao: specifies the PAO truncation threshold for (T)-TNOs, the default is linked to toltno.
tolri: specifies the threshold for selecting orbital and pair-specific auxiliary basis sets for the local RI approximation. If not given tolri is set to $10^{7/12} \times \sqrt{\texttt{tolpno}}$, which is the recommended value.
tolpair: specifies the energy threshold for selecting the significant pairs. If not given tolpair is set to $(0.1\times\texttt{tolpno})^{2/3}$
toltrip: specifies the energy threshold for selecting the significant triples. If not given toltrip is set equal to tolpair.
opnos: enables (on) or disables (off) for F12 calculations the use of OPNOs for the occupied orbital spaces in the projectors for the three-electron integrals. Default: on
tolcapno: sets for F12 calculations the truncation thresholds for the complementary auxiliary PNOs for the virtual spaces (CAPNOs) in the projectors for the three-electron integrals. If not specified, default values are calculated from the threshold tolpno.
tolosc: sets for F12 calculations the truncation thresholds for the orbital specific complementary auxiliary virtuals from which the CAPNOs are generated. If not specified, default values are chosen as 0.1 $\times$ the tolcapno thresholds, which is the recommended choice.
tolopno: sets for F12 calculations the truncation thresholds for the selection of PNOs for the occupied orbital spaces (OPNOs) in the projectors for the three-electron integrals. If not specified, default values are calculated from the threshold tolpno.
toloso: set for F12 calculations the truncation thresholds for the orbital specific auxiliary occupied orbitals from which the OPNOs are generated. If not specified, default values are chosen as 0.1 $\times$ the tolopno threshold, which is the recommended choice.
conv: The conv parameter gives the convergence threshold for the ground state energy as $10^{-\mathrm{conv}}$. The default threshold is $10^{-7}$.
oconv: The oconv parameter gives an additional threshold for the residual of the ground state equations as $< 10^{-\mathrm{oconv}}$. The default threshold is $10^{-3}$.
lindep: If the norm of a vector is smaller than $10^{-\mathrm{lindep}}$, the vector is assumed to be zero. This threshold is also used to test if a set of pre-PNOs is linear dependent. The default threshold is $10^{-10}$ if PAOs are used and $10^{-12}$ otherwise.
maxiter: gives the maximum number of iterations for the solution of the cluster equations, eigenvalue problems or response equations (default: 25).
mxdiis: is the maximum number of vectors used in the DIIS procedures for the ground state equations (default: 10).
maxred: not used in the current release.
scs: the opposite–spin scaling factor cos and the same–spin scaling factor css can be chosen. If scs is set without further input, the SCS parameters cos=6/5 and css=1/3 are applied.
sos: the SOS parameters cos=1.3 and css=0.0 are applied.

$rir12

for the description of this data group see Sec. 25.2.23.

25.2.25 Keywords for Module pnoccsd

25.2.25 Keywords for Module `pnoccsd`