Data and code for "Electron collision operator for weakly oriented H2O and the order of the orientation-dependent drift correction"

Data and reproducibility code for the article “Electron collision operator for weakly oriented H2O and the order of the orientation-dependent drift correction” (Paper II). The archive contains: the 400-point Born-completed Legendre-coefficient data (b₀, b₁) used in Fig. 2, together with the Paper-I axial asymmetry A_MT; selected fixed-nuclei T/K scattering matrices from the Paper-I UKRmol+ calculation (Zenodo DOI 10.5281/zenodo.23633642) for both the baseline 10⁻⁷ and the tightened 3×10⁻⁸ continuum-orthogonalization deletion thresholds; the general-incidence momentum-transfer kernel code (fast quadrature implementation validated against brute-force quadrature); the unitarized permanent-dipole high-partial-wave K-matrix completion and the orientation-expanded collision-operator post-processing code; the 27-point collision-operator table of Supplemental Table S1; the thermal coefficients H₂ and H_SE evaluated with a prescribed Maxwellian electron distribution (Supplemental Table S2); figure-generation code and final figures; verification scripts, historical run logs, and a column glossary. All operator and thermal quantities are post-processing of the archived fixed-nuclei scattering matrices; no new UKRmol+ scattering calculation is performed by this archive. The thermal coefficients are formal fixed-nuclei model quantities, not a self-consistent water-vapor swarm-mobility prediction; the model limitations are described in the article and its Supplemental Material.