Methods overview
What exists, grouped by family. Maturity varies a great deal between these — see What is validated before trusting any particular number.
| Family | Methods | Page |
|---|---|---|
| SCF | RHF, UHF, ROHF, KS-DFT, gradients | SCF and DFT |
| MP2 | RI, attenuated, SCS, OO, Laplace, MP3, LMP2 | The MP2 family |
| Coupled cluster | CCD, CCSD, (T), LinLCCD | Coupled cluster |
| Response | PDEP-RPA, G0W0, COHSEX, evGW, TDDFT | RPA and GW |
| Electron transfer | cDFT, \( H_{ab} \) couplings | Constrained DFT |
Infrastructure
Shared machinery underneath all of the above:
- QQR screening (Maurer, Lambrecht & Ochsenfeld 2012) and LinK exchange (Ochsenfeld, White & Head-Gordon 1998) for the Fock build
- Spherical and Cartesian basis support, with BSE-JSON and Gaussian-94 parsers
einsum!— a tensor-contraction macro routing contractions through BLAS3 GEMMs, used throughout the CC and MP3 code- Memory budgets — enforced allocation ceilings that refuse an oversized job with a named breakdown rather than letting it be OOM-killed
- Python bindings (pyo3) and a TOML-driven CLI
Properties
ESP at nuclei, electric field, static and atom-partitioned polarizabilities, Hirshfeld and Löwdin charges, density matrices, and NPZ export of ML-ready features for downstream generative-model conditioning.
A note on negative results
Several reduced-scaling approaches in this codebase are implemented and measured negative — they are documented as such rather than omitted:
- AO-sparse Laplace SOS-MP2 — truncation radius tracks the molecular diameter instead of saturating
- Local MP2 — the J build is still dense-from-RI, so no scaling claim is made
- TDHF/RPAx \( C_6 \) — stays ~60% low regardless of gap
Knowing which ideas did not work is part of the documentation.