Basis-set library roadmap

Branch: basissetdev. Source review: REVIEW_BASIS_SETS_2026-05-08.md.

This document translates the 2026-05-08 review into a concrete roadmap for the python/vibeqc/basis_library/ bundle. Each row below is one canonical basis-set name and gives:

  • Status as of audit on 0ac5fb9:

    • ✅ shipped — present under basis/

    • 🟡 partial — present but with gaps (e.g. only some elements)

    • ❌ missing — not bundled yet

    • 🚫 blocked — bundling depends on a feature that has not landed

  • Priority matching the review’s tiered recommendation

  • Source the canonical place to fetch the numbers from

  • Blockers any vibe-qc capability gap that must close first

Status snapshot

  • 142 basis-set files currently bundled in python/vibeqc/basis_library/basis/ (audit on 0ac5fb9).

  • 45 review-recommended bases missing as listed below.

  • Three pob bases are byte-clean against the upstream Bredow-group source after the Goal-1 audit (commit f059b37).

  • The pcseg / x2c / dhf / vDZP / pob-aux blocks are the largest outright gaps.

Top-of-stack priorities (Q3 2026)

  1. pcseg-n family (n = 0…4, plus aug-pcseg-n). Pure-Python / segmented contraction; highest review-priority “missing” item.

  2. Pople diffuse variants (6-31+G(d,p), 6-31++G(d,p), 6-311+G(d,p)). Low-effort wins; easy BSE pull.

  3. vDZP. New low-cost workhorse needed for ωB97X-3c. Requires ECP infrastructure (currently absent in vibe-qc — see “Blocked on libecpint” below).

  4. 3c modified bases (def2-mSVP, def2-mTZVP, def2-mTZVPP). These are the carriers for r²SCAN-3c, B97-3c, etc. Not useful standalone — must arrive together with gCP + D3/D4.

  5. Relativistic def2 family (x2c-{S,TZ,QZ}VPall, dhf-XVPP, def2-TZVP-DKH). Blocked on a relativistic Hamiltonian implementation (X2C / DKH2 / ZORA) — out of scope for basissetdev; flag as a feature request for the molecular chat.

  6. pob auxiliary basis (pob-*-jk). Hand-tuned aux for periodic density fitting. Already in Goal 5 of the basissetdev plan; AutoAux owned by the DF dev chat — see feedback_aux_basis_routing.md.

Cross-cutting prerequisites

Several review recommendations are blocked on infrastructure that the molecular / periodic dev chats own:

Prerequisite

Blocks

Owner chat

ECP integral support (libecpint)

LANL2DZ, vDZP, dhf-{S,TZ,QZ}VPP, x2c-{S,TZ,QZ}VPall, pob-rev2 fifth-period

molecular DF / SCF chat

Relativistic Hamiltonian (X2C / DKH2 / ZORA)

x2c-XVPall, dhf-XVPP, def2-TZVP-DKH meaningful use

molecular relativity chat (not yet spawned)

CP2K-style GPW / mixed Gaussian-PW basis

MOLOPT family

periodic chat (deferred)

PAW / ONCV pseudopotential infrastructure

PseudoDojo, SSSP, VASP-PAW

periodic chat (deferred — vibe-qc is Gaussian)

NMR shielding / J-coupling kernels

pcS-n, pcJ-n meaningful use

properties chat (not yet spawned)

AutoAux (Stoychev) implementation

“auto-fit aux for any orbital basis”

density-fitting chat

The big table

Everything the review recommends, organised by family. “BSE name” is the canonical Basis Set Exchange identifier; the fetch script (scripts/basisset_dev/fetch_from_bse.py, to be added) takes that as input.

Pople family

Name

BSE id

Status

Priority

Notes

STO-3G

STO-3G

✅

low

Pedagogy / SCF guess. UI label: “for guess only”.

STO-6G

STO-6G

✅

low

Same role as STO-3G; slightly better atomic energies.

MINI

MINI (Huzinaga)

✅

low

Niche.

3-21G

3-21G

✅

low

UI label: “unpolarised — avoid for production”.

6-31G

6-31G

✅

low

Same UI label as 3-21G.

6-31G(d)

6-31G*

✅

medium

Legacy default; keep.

6-31G(d,p)

6-31G**

✅

medium

Same.

6-31+G(d,p)

6-31+G**

❌

high

Diffuse-aug, missing.

6-31++G(d,p)

6-31++G**

❌

high

Best DZ basis per Pitman 2024. Missing.

6-311G(d,p)

6-311G**

✅

medium

UI label: “polarised 6-311G is poorly parameterised — prefer pcseg-2 / def2-TZVP” (Pitman 2024).

6-311+G(d,p)

6-311+G**

❌

medium

Diffuse variant.

6-311+G(2d,p)

6-311+G(2d,p)

❌

low

Less commonly used.

6-311+G(2df,p)

6-311+G(2df,p)

❌

low

Same.

Karlsruhe def2 family

Name

BSE id

Status

Priority

Notes

def2-SV

def2-SV

✅

medium

def2-SV(P)

def2-SV(P)

✅

medium

def2-SVP

def2-SVP

✅

high

Default DZ.

def2-SVPD

def2-SVPD

✅

medium

def2-TZVP

def2-TZVP

✅

highest

Production default.

def2-TZVPD

def2-TZVPD

✅

high

def2-TZVPP

def2-TZVPP

✅

high

def2-TZVPPD

def2-TZVPPD

✅

high

Inorganic main-group default.

def2-QZVP

def2-QZVP

✅

high

Benchmark DFT.

def2-QZVPP

def2-QZVPP

✅

high

def2-QZVPPD

def2-QZVPPD

✅

medium

ma-def2-TZVP

ma-def2-TZVP

❌

high

Truhlar minimally-augmented.

ma-def2-TZVPP

ma-def2-TZVPP

❌

medium

ma-def2-SVP

ma-def2-SVP

❌

medium

def2-universal-J

(built into def2-J)

✅

high

aux-fit, Coulomb

def2-universal-JK

(built into def2-JK)

✅

high

aux-fit, Coulomb+exchange

Karlsruhe def2 — relativistic (blocked on rel. Hamiltonian)

Name

BSE id

Status

Priority

Notes

x2c-SVPall

x2c-SVPall

🚫

high

Pollak-Weigend 2017. Blocked on X2C / DKH.

x2c-TZVPall

x2c-TZVPall

🚫

high

Same.

x2c-QZVPall

x2c-QZVPall

🚫

high

Franzke 2020.

x2c-TZVPall-s

x2c-TZVPall-s

🚫

medium

NMR-tuned.

dhf-SVP

dhf-SVP

🚫

medium

Dirac-Hartree-Fock-derived def2-equivalent.

dhf-TZVP

dhf-TZVP

🚫

medium

dhf-QZVP

dhf-QZVP

🚫

low

def2-TZVP-DKH

def2-TZVP-DKH

🚫

medium

DKH-recontracted.

Karlsruhe def2 — modified for 3c (blocked on gCP + D3/D4)

Name

BSE id

Status

Priority

Notes

def2-mSVP

def2-mSVP

🚫

high

PBEh-3c, B3LYP-3c carrier.

def2-mTZVP

def2-mTZVP

🚫

high

B97-3c carrier.

def2-mTZVPP

def2-mTZVPP

🚫

high

r²SCAN-3c carrier.

Dunning correlation-consistent

Name

BSE id

Status

Priority

Notes

cc-pVDZ

cc-pVDZ

✅

high

cc-pVTZ

cc-pVTZ

✅

high

Post-HF default.

cc-pVQZ

cc-pVQZ

✅

high

CBS extrapolation.

cc-pV5Z

cc-pV5Z

✅

medium

cc-pV6Z

cc-pV6Z

✅

low

cc-pV7Z

cc-pV7Z

✅

low

aug-cc-pVDZ

aug-cc-pVDZ

✅

high

aug-cc-pVTZ

aug-cc-pVTZ

✅

high

Anions, response.

aug-cc-pVQZ

aug-cc-pVQZ

✅

medium

aug-cc-pV5Z

aug-cc-pV5Z

✅

medium

cc-pV(D+d)Z

cc-pV(D+d)Z

❌

medium

“tight d” for hypervalent S/P.

cc-pV(T+d)Z

cc-pV(T+d)Z

❌

medium

cc-pV(Q+d)Z

cc-pV(Q+d)Z

❌

medium

aug-cc-pV(T+d)Z

aug-cc-pV(T+d)Z

❌

medium

cc-pCVDZ

cc-pCVDZ

❌

medium

Core-valence.

cc-pCVTZ

cc-pCVTZ

❌

medium

Core-valence.

cc-pCVQZ

cc-pCVQZ

❌

medium

Core-valence.

aug-cc-pCVTZ

aug-cc-pCVTZ

❌

medium

Core-valence.

cc-pwCVTZ

cc-pwCVTZ

✅

low

Weighted core-valence.

cc-pVTZ-F12

cc-pVTZ-F12

✅

medium

Explicit-correlation.

cc-pVQZ-F12

cc-pVQZ-F12

✅

medium

Jensen polarization-consistent (segmented + general)

Name

BSE id

Status

Priority

Notes

pc-0

pc-0

❌

medium

Unpol DZ.

pc-1

pc-1

❌

medium

DZ-pol.

pc-2

pc-2

❌

medium

TZ-pol.

pc-3

pc-3

❌

low

QZ-pol.

pc-4

pc-4

❌

low

5Z-pol.

pcseg-0

pcseg-0

❌

high

Segmented contraction.

pcseg-1

pcseg-1

❌

highest

DFT-optimal DZ.

pcseg-2

pcseg-2

❌

highest

DFT-optimal TZ — best on diet-GMTKN55 (Pitman 2024).

pcseg-3

pcseg-3

❌

medium

pcseg-4

pcseg-4

❌

low

aug-pcseg-1

aug-pcseg-1

❌

high

aug-pcseg-2

aug-pcseg-2

❌

high

TDDFT, anions.

pcS-0…3

pcS-{0,1,2,3}

🚫

medium

NMR shielding (blocked on NMR kernel).

pcJ-0…3

pcJ-{0,1,2,3}

🚫

medium

NMR J-coupling.

vDZP (Grimme 2023, blocked on libecpint)

Name

BSE id

Status

Priority

Notes

vDZP

vDZP

🚫

high

ωB97X-3c carrier; uses ECPs.

ANO families

Name

BSE id

Status

Priority

Notes

ANO-RCC (full)

ANO-RCC

✅

high

Generally contracted.

ANO-RCC-MB

ANO-RCC-MB

✅

low

Minimal.

ANO-RCC-VDZP

ANO-RCC-VDZP

❌

medium

Specific contraction.

ANO-RCC-VTZP

ANO-RCC-VTZP

❌

high

Multireference TM standard.

ANO-RCC-VQZP

ANO-RCC-VQZP

❌

medium

ANO-R0

ANO-R0

❌

medium

Zobel-Widmark-Veryazov 2020.

ANO-R1

ANO-R1

❌

medium

ANO-R2

ANO-R2

❌

medium

ANO-R3

ANO-R3

❌

low

LANL ECP (deprecated by review, ship for compatibility)

Name

BSE id

Status

Priority

Notes

LANL2DZ

LANL2DZ

🚫

low

UI label: “deprecated — use def2-TZVP + def2-ECP”. Blocked on libecpint.

Periodic Gaussian

Name

Source

Status

Priority

Notes

pob-TZVP

Bredow tarball

✅

highest

Verified byte-clean f059b37.

pob-DZVP-rev2

Bredow scrape

✅

high

Verified.

pob-TZVP-rev2

Bredow tarball

✅

highest

Verified. S d-shell bug fixed.

pob-DZVP (original)

Bredow archive

❌

medium

Predecessor of rev2; for reproducibility.

pob-DZVPP

Bredow archive

❌

medium

Polar augmentation.

pob-TZVPP

Bredow archive

❌

medium

Polar augmentation.

pob-TZVP-rev2 (Rb-I, fifth period)

Bredow tarball

🚫

high

Blocked on libecpint (5th period uses ECPs).

pob-TZVP-jk

(to design)

🚫

high

Goal 5 of basissetdev.

MOLOPT-SZV

CP2K source

🚫

medium

Blocked on GPW infrastructure.

MOLOPT-DZVP

CP2K source

🚫

medium

MOLOPT-TZVP

CP2K source

🚫

medium

MOLOPT-TZV2P

CP2K source

🚫

medium

dcm-TZVP

Daga/Civalleri/Maschio 2020

❌

low

System-specific (diamond, graphene, carbyne).

Property-specific (blocked on property kernels)

Name

BSE id

Status

Priority

Blocks

EPR-II

EPR-II

🚫

medium

EPR g-tensor / hyperfine kernel

EPR-III

EPR-III

🚫

medium

Same

Sadlej-pVTZ

Sadlej pVTZ

❌

medium

Polarizability — kernel exists

LPolX (Maroulis)

(BSE varied)

❌

low

Same

ccX-DK

ccX-DK

❌

low

Core-level X-ray

Plane-wave / NAO / LAPW (out of scope today)

The review recommends VASP-PAW, PseudoDojo (ONCV), SSSP, GBRV, SG15, JTH PAW, FHI-aims tier 1-4, SIESTA NAO, and (L)APW+lo. vibe-qc is a Gaussian / atom-centred-orbital code today; none of these libraries fit the current architecture. The roadmap captures them under “deferred to a future periodic-PW chat”:

  • PseudoDojo (ONCV) is the recommended starting point if / when vibe-qc grows a plane-wave path. Open-source, well-curated, has scalar and fully-relativistic variants.

  • SSSP precision is the natural complement for high-throughput materials work.

  • PAW (VASP / GPAW / ABINIT JTH) is a substantial implementation lift via the projector formalism; defer until ONCV is stable.

  • FHI-aims tier-1/2 NAO would require a numerical-orbital integral path entirely separate from libint.

Inventory dashboard

A live summary belongs in python/vibeqc/basis_library/README.md. The current README inventory predates this roadmap; updating it to flag missing-and-prioritised items is part of the next basissetdev deliverable. The dashboard format I propose:

def2-TZVP        ✅  shipped
pcseg-2          ❌  missing — high priority — fetch from BSE
ma-def2-TZVP     ❌  missing — high priority — fetch from BSE
x2c-TZVPall      🚫  blocked on relativistic Hamiltonian
vDZP             🚫  blocked on libecpint integration

so users can see at a glance what they cannot use and why.

Tooling: BSE fetcher

Most of the missing all-electron bases are one HTTP call away from completion. Sketch (to land in scripts/basisset_dev/fetch_from_bse.py):

from basis_set_exchange import api
text = api.get_basis(name="pcseg-2", elements=None,
                     fmt="gaussian94", header=True)
Path(f"python/vibeqc/basis_library/custom/{name}.g94").write_text(text)

pip install basis-set-exchange ships a curated copy of the BSE database; the call is offline-friendly. The fetcher will:

  1. Read the “missing” list from this roadmap (parse the table).

  2. Pull each via BSE.

  3. Drop into custom/ per the existing convention.

  4. Run scripts/setup_basis_library.sh to copy custom/ → basis/.

  5. Add a regression-test that verifies every name resolves under LIBINT_DATA_PATH and is parseable by libint.

Action items (ordered)

  1. Land BSE fetcher + commit pcseg-{0,1,2,3,4} and 6-31++G(d,p) + 6-31+G(d,p) + 6-311+G(d,p) + ma-def2-{TZVP,SVP} + aug-pcseg-{1,2}. Pure-Python additions; no infrastructure blockers.

  2. Update basis_library/README.md with the dashboard view.

  3. File ECP-integral feature request with the molecular DF / SCF chat (libecpint integration unlocks LANL2DZ + vDZP + dhf-XVP + x2c-XVPall + 5th-period pob).

  4. File relativistic-Hamiltonian feature request with a future molecular-relativity chat (X2C / DKH2 / ZORA — unlocks the x2c / dhf families’ meaningful use).

  5. 3c composite methods as a downstream goal once vDZP and def2-m{S,TZ,TZP}VP are in place AND gCP + D3/D4 are wired through the molecular runner.

  6. Goal 5 of basissetdev: bespoke pob-*-jk auxiliary basis (separate paper; not blocked on the missing all-electron bases above).

Cross-references

  • PLAN.md — top-level basissetdev plan; this roadmap is rolled in as a new long-term goal slot.

  • REQUIREMENTS-PERIODIC.md — handover to the periodic chat; the periodic-Gaussian items above partly depend on R1-R5 there.

  • GOAL4_DESIGN.md — basis-optimisation engine design; note: the optimiser will eventually generate basis sets that themselves go into this library (Goal 5: bespoke pob-*-jk; Goal 6: periodic metals basis).