= BDF-G: Gaussian function based BDF (Beijing Density Functional) program package =
<<TableOfContents()>>

== Version history ==
The Gaussian function based BDF program started in 2009 based on several contributions from previous group members.

''Compared with other quantum chemistry programs, it mainly focuses on '''relativistic effects''' and '''excited-state properties''' of '''large molecules'''. ''

Currently, it is not open to everyone, since we are still trying to make it easier to use.

However, if you are interested in using it '''for the above problems''', please contact the authors for collaboration:

 * Wenjian Liu: https://www.researchgate.net/profile/Wenjian_Liu
 * Bingbing Suo: https://www.researchgate.net/profile/Bingbing_Suo
 * Zhendong Li: https://www.researchgate.net/profile/Zhendong_Li4
 * ..... 


== List of features ==
=== Current features ===
 * Relativistic Hamiltonians: sf-X2C/SOMF
 * R,RO,U SCF ([[scf]]): Hatree-Fock and DFT
 * Variants of TD-DFT ([[tddft]]), with special emphasis on open-shell TD-DFT, SOC effects at the TD-DFT level, and internal roots (e.g. core excitations) at the TD-DFT level
 * MP2 ([[mp2]]) and Local MP2 based on fragmentations
 * Geometry optimization, numerical Hessian and thermochemistry analysis ([[bdfopt]])
 * MCSCF ([[mcscf]]): Multi-configuration self-consistent-field
 * Localmo ([[localmo]]): Orbital localization by localization functionals.
 * Expandmo ([[expandmo]]): AVAS for active space selection and expand molecular orbital from a small basis set into a large basis set.
 * Gradient ([[grad]] and [[resp]]): SCF, DFT, TDDFT and (SA-)CASSCF analytic gradients 
 * Response properties ([[resp]]): DFT and TDDFT non-adiabatic coupling matrix elements, polarizabilities, hyperpolarizabilities etc.
 * Numerical Gradient ([[numgrad]]): Numerical gradient for SCF, DFT, TDDFT, MCSCF and Multi Reference methods in xianci module
 * MOs integrals transformation ([[traint]]): MOs integrals transformation for TDDFT, FULL-CI, MRCI, MRPT2 and other Post-HF methods.
 * VGMF-CI [[[vgmfci]]]: Vibrational General Mean Field Configuration interaction
 * NMR: Nuclear Magnetic Resonance 
 * MRCISD: from uncontracted to fully internally contracted MRCI,
 * MRPT2: Various MRPT2 methods include MS-NEVPT2/3, SDS-PT2, CB-MRPT2/3
 * CCSD,EOM-CCSD: Coupled Cluster Theory developed in Sihuan University (Prof. Fan Wang).
 * REM: Renormalize Exciton Method developed by Nanjing University. (Prof. Jing Ma. Prof. Haibo Ma)
 * NTO analyze: Natrual transition orbital analyze based on TDDFT/TDHF
 * Two diabatic states coupling to calculate energy transfer and charge transfer integrals. 

=== Package developed by other groups that are Interfaced or integrated into BDF ===
 * CC with SOC [[ccsdso]] (Fan Wang)
 * UND-MCSCF -- Developed by Mark Hoffman in North Dakota University
 * MCCEPA 
 * DETCI
 * Xi'an-CI Program [[xianci]] -- Developed by Zhenyi Wen, Yubin Wang, Zhengting Gan, Bingbing Suo and Yibo Lei in Northwest University 
 * GEBF -- Developed by Nanjing University
 * dlfind 
 * libcint
 * xcfun
 * libxc
 * UniMoVib (Wenli Zou)

=== Under development ===

=== Future development ===
 * [[Large-scale DFT/TD-DFT and heterogeneous computing]] (Bingbing Suo)
 * [[2C and 4C DHF/KS]] (Daoling Peng)
 * [[NMR and NSR]] (Yunlong Xiao)
 * [[QM/MM]] (Jun Gao)
 * Interface to dynamics (Jun Gao)

== Recent major changes ==

'''2019.11.28: By Bingbing Suo: BDF easy input'''

A important progress for users. BDF now supports a simplified input style. see [[bdfeasyinput]]

== Known problems ==

[[KnownProblems]] 

== Quick start ==
To get a quick start, please refer to the examples in '''bdf-pkg/tests/input/'''.

 * [[Define your own basis set]]

 * [[Change the amount of HF exchange in functionals]]

 * [[Nonabelian symmetry]]
 
 * Characters in BDF input are case insensitive. However, the name of basis set file should be capital letters such as "CC-PVDZ". The environment variables such as BDFHOME, BDF_TMPDIR, BDF_WORKDIR should be capital letters. 

== Programs ==
The following programs are listed in '''bdf-pkg/database/program.dat'''. If there is any problem or question, please contact the corresponding authors.
||'''[[Program]]''' ||'''Brief introduction''' ||'''Main authors''' ||
||[[compass]] ||几何结构 ||Bingbing Suo ||
|| ||
||[[xuanyuan]] ||积分计算 ||Bingbing Suo ||
|| ||
||[[scf]] ||SCF (KS and HF) ||Bingbing Suo, Zhendong Li ||
|| ||
||[[traint]] ||积分变换 ||Bingbing Suo ||
|| ||
||[[tddft]] ||TD-DFT ||Zhendong Li, Bingbing Suo ||
|| ||
||[[resp]] ||DFT-response theory ||Zhendong Li ||
|| ||
||mp2 ||MP2 ||Bingbing Suo ||
|| ||
||[[localmo]] ||localization || ||
|| ||
||[[bdfopt]] ||Geometry optimization ||Bingbing Suo, Zhendong Li ||
|| ||
||[[nmr]] ||NMR ||Minghong Yuan ||
|| ||
||[[mcscf]] ||MCSCF || Bingbing Suo, Yibo Lei||
|| ||
||[[grad]] || Analytic Gradients - RHF and MCSCF ||Bingbing Suo, Yibo Lei ||
||[[numgrad]] || Numerical Gradients - RHF, MCSCF, Xi'an-CI methods ||Yibo Lei ||
|| ||
||[[expandmo]] ||AVAS method and expand MO coefficients from a small basis set to a large basis set ||Bingbing Suo, Yibo Lei ||
|| ||
||[[atom]] ||Atom calculations ||Zhendong Li ||
|| ||
||drt ||DRT ||Yibo Lei, Yubin Wang, Bingbing Suo, Zhenyi Wen ||
||mrci ||MRCI ||Yibo Lei, Yubin Wang, Bingbing Suo, Zhenyi Wen ||
|| [[xianci]] || MRCI from uncontracted to fully internally contracted MRCI, Various MRPT2 methods || Yibo Lei, Yubin Wang, Bingbing Suo, Zhenyi Wen||
|| ||
||dhf ||Dirac-HF ||Zhendong Li ||
||relscf ||REL-SCF ||Bingbing Suo ||
|| ||
||fci ||FCI without symmetry ||Zhendong Li ||
|| ||
||[[ccsdso]] ||CCSDSO ||Fan Wang ||
||eomipso ||EOM-IP-SO ||Fan Wang ||
||eomeaso ||EOM-EA-SO ||Fan Wang ||
||eomeeso ||EOM-EE-SO ||Fan Wang ||
|| ||
||libmath_test ||test for math libraries ||Zhendong Li ||
|| ||
||genfrag ||Fragments ||Bingbing Suo ||
|| ||
||mcmp2 ||Monte-Carlo MP2 (unfinished) ||Zhendong Li ||
|| ||
||[[vgmfci]] ||VGMFCI ||Bingbing Suo, Patrick Cassam-Chenaï||
|| ||
||mccepa ||MC-CEPA || ||
|| ||
||x2c ||useful Remove latter || ||
||traintmc ||AO-MO Integral transformation for undmcscf ||Bingbing Suo ||
||undmcscf ||MCSCF from undmol ||Bingbing Suo ||
||rhfscf ||??? || ||
||mrso ||Spin-orbital coupling based on GUGA, in developing ||Bingbing Suo ||
||trnx ||??? || ||
||guess ||Initial guess orbital ||Remove latter ||
||properties ||??? || ||
||reorderorb ||Reorder orbital for undmcscf ||Bingbing Suo ||
||socint ||Spin-orbital coupling integral ?? || ||
||contsi ||Constraint state interaction CI, in developing || ||
||strmcrcfgs ||String-CI (Hoffmann) ||interfaced ||
||strci ||String CI || ||
||norbord ||Interface for undmcscf || ||
||[[noxci]] ||non-orthogonal MRCID(with double excitation contracted ) ||Chao Huang ||
||[[nrcc]] ||non-relativistic restricted CCD/CCSD/EOM-CCSD||Chao Huang ||
||[[corr2]] ||(SR)MP2,Epstein-Nesbet PT2,IEPA, etc double excitation correlation (Energy& Coefficient)   ||Chao Huang ||



== Source ==
In general, there are two kinds of folder in bdf-pkg/source. One type of folders with suffix "_util" (such as scf_util) corresponds to folders that do not contain a main program. They contain library routines shared or used by different programs. The other type of folders (such as scf) corresponds to folders which contain a main.F90 program. Source codes in these folder are compiled and linked to an executable files with the name "foldername.x" and are saved in directory bdf-pkg/bin.

Folders in '''bdf-pkg/source''':
||'''Folder''' ||'''Description''' ||
||atom || ||
||atom_mod || ||
||atom_util || ||
||bdf_cvwint2e || ||
||bdf_opencl_util ||System util of OpenCL support in BDF ||
||bdf_rel1e || ||
||bdf_rel1e_NRpart || ||
||bdf_rel2e || ||
||bdf_relbas || ||
||bdf_relmod || ||
||bdf_relshl || ||
||bdf_x2c || ||
||c_util || ||
||cbmrpt2 || ||
||ccsdso || ||
||ccsdso_util || ||
||cdri_util || ||
||ci_util || ||
||cl_dft_kernel ||OpenCL kernels for DFT, C99 language ||
||class || ||
||compass || ||
||contsi || ||
||corr2 || ||
||detci || ||
||dft ||Share library of DFT, should be changed to dft_util ||
||dhf || ||
||dpdmrpt2 || ||
||drt || ||
||ecpint_util || ||
||eomeaso || ||
||eomeaso_util || ||
||eomeeso || ||
||eomeeso_util || ||
||eomipso || ||
||eomipso_util || ||
||erd ||Remove later ||
||erd_ACESIII ||Remove later ||
||eri_util ||Library for ERI and gradients calculation ||
||exact2c_util || ||
||extra_lib || ||
||f77_cg || ||
||f77_dftd3 || ||
||f77_util || ||
||f77_xc ||XC functional Fortran 77 code ||
||fci || ||
||flmo_util || ||
||fmm_util ||Faster multipole library - in developing ||
||geom_opt || ||
||grad_util ||Share library for gradients ||
||group_util ||Share library for point group untility ||
||icci_new_918 || ||
||icoord_mod || ||
||include ||Fortran and C head files ||
||int1e_util ||Library of 1e integrals ||
||int_util ||Library of 2e integrals ||
||lagrangian || ||
||libecctrip || ||
||libmath_f77 || ||
||libmath_mod || ||
||libmath_test || ||
||libmath_util || ||
||libmathc_util || ||
||libr || ||
||librcc || ||
||libundmol || ||
||list || ||
||localmo || ||
||mathlib || ||
||mccepa || ||
||mccepa_util || ||
||mcci || ||
||mcgugaci_util || ||
||mcmodule || ||
||mcmp2 || ||
||mcrcfgs || ||
||mcscf || ||
||mcscf_util || ||
||mctpdmcfg || ||
||mctrans || ||
||module || ||
||mp2 || ||
||mrci || ||
||mrso || ||
||nmr || ||
||nmr_mod || ||
||norbord || ||
||noxci || ||
||noxci_util || ||
||opdmcfg || ||
||orbhess || ||
||orbord || ||
||orbxcsfcfg || ||
||para_util ||Library for parallel calculation. ||
||pmrci || ||
||postscf || ||
||properties || ||
||relint1e_util || ||
||relint2e_util || ||
||relscf || ||
||reorderorb || ||
||resp ||driver of response ||
||resp_f77 || ||
||resp_mod || ||
||resp_util || ||
||respc_util || ||
||scf ||SCF program ||
||scf_util ||Library of SCF ||
||socint || ||
||soint_util || ||
||strci || ||
||strmcrcfgs || ||
||sys_util ||System libraries such as IO, system initialization ||
||tddft ||TDDFT ||
||tddft_props || ||
||tddft_util ||Share library of TDDFT ||
||tddftc || ||
||tidyorb || ||
||tools || ||
||tpdmcfg || ||
||traint || ||
||traint_util || ||
||traintmc || ||
||undmcscf || ||
||undmol_drv || ||
||undmol_util || ||
||vgmfci || electron-nuclei mean field configuration interaction routines ||
||x2c || ||
||xuanyuan || ||
||xianci || Interfaced with Xi'an-CI program developed in Northwest University ||
== Citations ==
'''Historical papers about the BDF package''':

Y. Zhang, B. Suo, Z. Wang, N. Zhang, Z. Li, Y. Lei, W. Zou, J. Gao, D. Peng, Z. Pu, and Y. Xiao, Q. Sun, F. Wang, Y. Ma, X. Wang, Y. Guo, W. Liu, BDF: A relativistic electronic structure program package. J. Chem. Phys. 152(6), 064113 (2020).

W. Liu, G. Hong, D. Dai, L. Li, and M. Dolg, Theor. Chem. Acc. 96, 75 (1997).

W. Liu, F. Wang, and L. Li, J. Theor. Comput. Chem. 2, 257 (2003).

W. Liu, F. Wang, and L. Li, in Recent Advances in Relativistic Molecular Theory, Recent Advances in Computational Chemistry, Vol. 5, edited by K. Hirao and Y. Ishikawa (World Scientific, Singapore, 2004), p. 257.

W. Liu, F. Wang, and L. Li, in Encyclopedia of Computational Chemistry (electronic edition), edited by P. von Ragu\'e Schleyer, N. L. Allinger, T. Clark, J. Gasteiger, P. A. Kollman, H. F. Schaefer III, and P. R. Schreiner (Wiley, Chichester, UK, 2004).

'''Spin-adapted open-shell TD-DFT''':

Zhendong Li and Wenjian Liu, “Spin-adapted open-shell random phase approximation and time-dependent density functional theory. I. Theory”, J. Chem. Phys. 133, 064106 (2010).

Zhendong Li, Wenjian Liu, Yong Zhang, and Bingbing Suo, “Spin-adapted open-shell time-dependent density functional theory. II. Theory and pilot application”, J. Chem. Phys. 134, 134101 (2011).

Zhendong Li and Wenjian Liu, “Spin-adapted open-shell time-dependent density functional theory. III. An even better and simpler formulation”, J. Chem. Phys. 135, 194106 (2011).

'''Spin-flip TD-DFT''':

Zhendong Li and Wenjian Liu, “Theoretical and numerical assessments of spin-flip time-dependent density functional theory”, J. Chem. Phys. 136, 024107 (2012).

'''TD-DFT with SOC based on spin-free exact two-component (sf-X2C) and spin-orbit mean-field (SOMF) operator''':

Zhendong Li, Yunlong Xiao, and Wenjian Liu, “On the spin separation of algebraic two-component relativistic Hamiltonians”, J. Chem. Phys. 137, 154114 (2012).

Zhendong Li, Yunlong Xiao, and Wenjian Liu, “On the spin separation of algebraic two-component relativistic Hamiltonians: molecular properties”, J. Chem. Phys. 141, 054111 (2014).

Zhendong Li, Bingbing Suo, Yong Zhang, Yunlong Xiao, and Wenjian Liu, “Combining spin-adapted open-shell TD-DFT with spin-orbit coupling”, Mol. Phys. 111, 3741 (2013).

'''TD-DFT and pp-TDA based first-order nonadiabatic coupling matrix elements (fo-NACMEs)''':

Zhendong Li and Wenjian Liu, "First-order nonadiabatic coupling matrix elements between excited states: A Lagrangian formulation at the CIS, RPA, TD-HF, and TD-DFT levels", J. Chem. Phys. 141, 014110 (2014).

Zhendong Li, Bingbing Suo, and Wenjian Liu, "First-order nonadiabatic coupling matrix elements between excited states: II. Implementation and applications at the TD-DFT and pp-RPA levels", J. Chem. Phys. 141, 244105 (2014).

'''Fragment Local Molecular Orbital''':

Zhendong Li, Hongyang Li, Bingbing Suo, Wenjian Liu, "Localization of molecular orbitals: from fragments to molecule", Accounts of chemical research, 47(9), 2758-2767, 2014.

Hongyang Li, Wenjian Liu, Bingbing Suo, "Localization of open-shell molecular orbitals via least change from fragments to molecule", J. Chem. Phys. 146, 104104, 2017.