QVF-Basis – Conversion Fidelity Matrix

Which fields survive a round-trip from the QVF-Basis canonical model to each target format and back?

Field	QVF-Basis	BSE JSON	G94	ORCA	NWChem
schema_version	✅	✅ (set to “1.0.0”)	❌	❌	❌
name	✅	✅	❌ (comment only)	❌	✅ (header)
description	✅	✅	❌	❌	❌
role	✅	✅	❌	❌	❌
basis_family	✅	✅	❌	❌	❌
elements	✅	✅	✅	✅	✅
element symbol	✅	✅	✅	✅	✅
angular_momentum	✅	✅	✅ (via labels)	✅	✅
SP shell	✅ (explicit [0,1])	✅	✅ (SP label)	✅ (S+P blocks)	✅ (S+P blocks)
harmonic_type	✅	✅ (default: spherical)	❌	❌	✅ (global header)
exponents	✅	✅	✅	✅	✅
coefficients	✅	✅	✅	✅	✅
primitive ordering	✅ (descending)	✅	✅	✅	✅
ecp_electrons	✅	✅	❌	❌	❌
ECP potentials	✅	✅	❌ (separate file)	❌	❌ (separate block)
references / DOI	✅	✅	❌	❌	❌
provenance	✅	✅ (version only)	❌	❌	❌
parent basis link	✅	❌ (not in BSE)	❌	❌	❌
segmented contraction	✅ (implicit)	✅	✅	✅	✅
general contraction	✅ (implicit)	✅	⚠️ (expanded)	⚠️ (expanded)	⚠️ (expanded)

Legend:

• ✅ = round-trips faithfully

• ⚠️ = survives but with information loss (general → segmented expansion)

• ❌ = lost entirely

Loss summaries by format

G94

7 fields dropped: name, description, role, basis_family, references, provenance, harmonic_type. ECPs must go in a separate file. General contractions are expanded to segmented form.

ORCA

7 fields dropped: same as G94. The %basis block is an input directive, not a storage format. ECPs are separate. General contractions are expanded.

NWChem

7 fields dropped (same set). ECPs require a separate ecp directive (not emitted). harmonic_type is partially preserved as global spherical/cartesian keyword.