Xi'an-CI
Contents
Xi’an-CI program generates Multi Reference SDCI (MRCISD) wavefunctions (including internal contracted MRCISD on several different level accuracy), Multi Reference Second Order Perturbation Theory (including multi-state NEVPT2 (MS-NEVPT2), Multi Reference Third Order Perturbation Theory (SS-NEVPT3), Static-Dynamic-Static Second Order Perturbation Theory (SDSPT2), Static-Dynamic-Static Configuration Interaction (SDSCI), Configuration Based Multi Reference Second Order Perturbation Theory (CB-MRPT2) and Configuration Based Multi Reference Third Order Perturbation Theory (CB-MRPT3). This program is based on hole-particle symmetry based and GUGA for the computation of CI matrix elements. The program can calculate several eigenvectors simultaneously. Xi’an-CI program is written by Zhenyi Wen, Yubin Wang, Zhengting Gan, Bingbing Suo and Yibo Lei (Institute of Modern Physics, Northwest University, China).
General keywords
Comment:
If no keyword is used, xianci module will read information from mcscf and traint modules and then calculate Fully internal contracted MRCISD.
nroot
- State Number
Example:
Electron
- CI effective electron Number without electrons of frozen MOs in traint module for MO integral transformation
Example:
Symmetry
- Symmetry of the target state.
Example:
Spin
- Spin multiplicity. 2S+1
core
- Number of frozen orbitals in each irreps, which must be missing or set to zero in each irreps if it has frozen MOs in traint module.
Example:
Inactive
- Number of inactive orbitals in each irreps.
Example:
Active
- Number of active orbitals in each irreps.
Example:
Comment:
If the above keywords are not set. the mcscf and traint modules information will be used.
Maxiter
- Maximum iteration Number of MRCISD. The default value is 500.
Example:
Maxiter 50
NODE
- Maximum DRT node number. The default value is 100000.
Example:
NODE 100000
WEI
- Maximum DRT WEI number. The default value is 500000.
Example:
WEI 500000
PLOOP
- Maximum partial LOOP number. The default value is 500000.
Example:
PLOOP 500000
SETICF
- Maximum partial internal CSFs number in active space. The default value is 500.
Example:
SETICF 500
SETDXY
- Maximum CI subspace in active space (DXY). The default value is 50000.
Example:
SETDXY 50000
SETH0
- Maximum reference CSF number. The default value is 500000.
Example:
SETH0 500000
MAXLOOP
- Maximum partial LOOP number for CI acceleration which is larger than or equal to keyword 'PLOOP' set value. The default value is 500000.
Example:
MAXLOOP 500000
PLBLK
- Maximum partial LOOP block number. The default value is 500000.
Example:
PLBLK 500000
CITHR
- set threshold for CI vector print. The default value is 0.05.
Example:
CITHR 0.1
Conv
- set threshold for CI energy, CI vector and Residual vector of MRCISD, respectively. The default value is set as the following example.
Example:
Conv 1.d-8 1.d-6 1.d-8
UCCI
- This keyword is set for un-contracted MRCISD.
Example:
UCCI
FCCI
- Default for internal contraction module. This keyword is set for Fully internal Contraction module of CSFs, reference CSFs are not contracted for MRCISD calculation, while perturbation theory calculation all CI subspaces are internally contracted.
Example:
FCCI
NICI
- This keyword is set for one internal Contraction module of CSFs, only internal CI subspaces are not contracted.
Example:
NICI
CWCI
- This keyword is set for one internal Contraction module of CSFs, corresponding to keyword 'mrcic' in Molpro program for Celani-Werner (CW) contraction, where only CI subspaces VV, DV, DDV and VD in hole-particle symmetry are not contracted.
Example:
CWCI
WKCI
- This keyword is set for one internal Contraction module of CSFs, corresponding to keyword 'mrci' in Molpro program for Werner-Knowles (WK) contraction, where only CI subspaces with two electron excitation to external spaces are contracted.
Example:
WKCI
SDCI
- This keyword is set for one internal Contraction module of CSFs, the accuracy of which is more accurate than CWCI but less than WKCI. In contrast with WKCI module, CI subspaces with two electron excitation from hole space and meanwhile one electron excitation to external space are also contracted.
Example:
SDCI
Comment:
If no keyword is set for perturbation theory calculation in the following, xianci module will calculate MRCISD in default.
NEVPT2
- set for SS-NEVPT2 and MS-NEVPT2 calculations, where each reference state expands a specific CI space.
Example:
NEVPT2
MR-NEVPT2
- set for SS-NEVPT2 and MS-NEVPT2 calculations, where all reference states expand only one multi-states CI space.
Example:
MR-NEVPT2
NEVPT3
- set for SS-NEVPT3 calculation, where each reference state expands a specific CI space.
Example:
NEVPT3
SDSPT2
- set for SDSPT2 calculation, where all reference states expand only one multi-states CI space.
Example:
SDSPT2
SDSCI
- set for SDSCI calculation, where all reference states expand only one multi-states CI space.
Example:
SDSCI
NOLAN
- set for SDSPT2 and SDSCI calculations, where no Lanczos wavefunctions are used to produce Ps wavefunction in SDSPT2 and SDSCI.
Example:
NOLAN
NDIMPS
- set for SDSPT2 and SDSCI calculations, where CASSCF wavefunctions are used to produce Ps wavefunction in SDSPT2 and SDSCI.
Example:
NDIMPS 2 # two high-lying CASSCF wavefunctions are used to produce Ps wavefunction in SDSPT2 and SDSCI relative to reference wavefunctions.
Comment:
If Keyword 'NDIMPS' are not set or set to zero and keyword 'NOLAN' are set, SDSPT2 or SDSCI has no Ps wavefunction.
CBMRPT2
- set for CB-MRPT2 calculation, where each reference state expands a specific CI space.
Example:
CBMRPT2
MR-CBMRPT2
- set for CB-MRPT2 calculations, where all reference states expand only one multi-states CI space.
Example:
MR-CBMRPT2
MR-CBMRPT3
- set for CB-MRPT3 calculations, where all reference states expand only one multi-states CI space.
Example:
MR-CBMRPT3