I: Basic Features for PySOC:
(code: pysoc.tar.gz; short tutorial: pysoc.pdf)

a. evaluation of spin-orbit coupling elements between singlet and triplet states
b. Python scripts + FORTRAN
c. interfaced to third-party quantum chemistry packages, such as Gaussian 09 and DFTB+
d. based on Casida’s wave functions in LR-TDDFT, TDA, TDDFTB
e. Breit-Pauli spin-orbit Hamiltonian with effective charge approximation

II: Reference and citation to PySOC code:

Evaluation of Spin-Orbit Couplings with Linear-Response Time-Dependent Density Functional Methods
Xing Gao, Shuming Bai, Daniele Fazzi, Thomas Niehaus, Mario Barbatti, and Walter Thiel
J. Chem. Theory Comput., 2017, 13 (2), pp 515–524

DOI: 10.1021/acs.jctc.6b00915

III: Note for MolSOC:
(code: molsoc.tar.gz)
atomic integrals in PySOC are calculated from MolSOC code developed by Sandro Giuseppe Chiodo et al.
citation to MolSOC code: Computer Physics Communications 185 (2014) 676–683