CPPE: An Open-Source C++ and Python Library for Polarizable Embedding

Abstract

We present a modular open-source library for polarizable embedding (PE) named Cppe. The library is implemented in C++, and it additionally provides a Python interface for rapid prototyping and experimentation in a high-level scripting language. Our library integrates seamlessly with existing quantum chemical program packages through an intuitive and minimal interface. Until now, Cppe has been interfaced to three packages, Q-Chem, Psi4, and PySCF. Furthermore, we show Cppe in action using all three program packages for a computational spectroscopy application. With Cppe, host program interfaces only require minor programming effort, paving the way for new combined methodologies and broader availability of the PE model. 2

PSI4 1.4: Open-source software for high-throughput quantum chemistry

“…Psi4 now supports the polarizable embedding (PE) model 243,244 through the cppe library. 196 In the PE model, interactions with the environment are represented by a multi-center multipole expansion for electrostatics, and polarization is modeled through dipole polarizabilities usually located at the expansion points. The interface to the cppe library is entirely written in Python and supports a fully self-consistent description of polarization for all SCF methods inside Psi4.…”

Polarizable embedding QM/MM: the future gold standard for complex (bio)systems?

“…In order to couple such a library to an existing QM package, the user needs to take care of high-level driver routines, that handle the interface between the QM package, mainly calling its internal integrals routines, and the library itself, updating then the energy, the Fock matrix, or other QM quantities for coupling with post-SCF treatments. This strategy is implemented in the CPPE library 76 and is very promising, as it allows one to add the capability to treat a polarizable embedding to any QM software without the need to deal with the cumbersome details of the electrostatics involved. Moreover, the open source nature of the project makes this interface very appealing and could actually help to make polarizable QM/MM much more broadly available in QM software packages.…”

adcc: A versatile toolkit for rapid development of algebraic‐diagrammatic construction methods

“…Consequently, the absorption cross section is high, and the transition is strongly red-shifted in the embedded systems compared to vacuum. Rather than discussing the properties of nile red, which has been done in previous work [45], the given example shows that adcc is capable of tackling systems of medium size with good performance. As explained before, full flexibility is still granted, here by a) computing perturbative corrections to the ADC excitation energies and b) generating NTOs in user code with negligible programming effort.…”

“…Using pyscf as host program, three singlet excited states were computed at the ADC(2)/cc-pVDZ [35] hardware details). The PE-HF ground state calculations in pyscf employed cppe [45], which is also a modular python library. Perturbative corrections of the excitation energies [44] were computed directly in the python job scripts.…”