This file lists the properties in AtomDB, together with their format. For any of these properties, a "promolecular" value should be possible to define. It will generally be either a mean (perhaps a geometric mean or an l-infinity mean) or a sum of the atomic properties.
Scalars:
Given the atomic number, charge (default to zero), multiplicity (default to ground state of species with that charge and multiplicity), and excitation-level (default to lowest-energy state for a given charge and multiplicity). When fractional charge/multiplicity is provided, the correct thing to do is to define the value from the convex hull. Fractional excitation is not something I know how to support, except perhaps when the fractional occupation is less than one.
[ ] Ionization potential.
[ ] Electron affinity. (same raw data as ionization potentials but accessed differently)
[ ] Atomic radii (as many definitions as possible)
[ ] chemical potentials (benchmark values via the Mulliken-Donnelly-Parr-Levy-Palke definition)
[ ] hardness (benchmark values via the Parr-Pearson definition)
[ ] spin-chemical potential vectors (both native and valence-state-averaged; both {N,S} and {N_alpha,N_beta} representations.)
[ ] spin-hardness matrices (both native and valence-state averaged; both {N,S} and {N_alpha,N_beta} representations.)
[ ] polarizability. I think the best/easiest data is from here, which corresponds to this literature reference. See Thakkar and NIST. Thakkar also has quadrupole polarizabilities. Accurate Noble-Gas data from J. Chem. Phys. 153, 174304 (2020) Thakkar and this last reference include data for selected cations/anions.
[ ] softness and spin-softness. (Just utilities to link to the hardness values)
Vectors:
[ ] Orbital energies (HF and/or DFT level). Utility routines for finding the HOMO/LUMO energy should be there, and could be considered "scalar properties" individually.
[ ] Atomic density. (spline of values at specified points.)
[ ] Core atomic density. (spline)
[ ] Valence atomic density (spline)
[ ] kinetic-energy density
[ ] Kohn-Sham potential (wish list; perhaps far off except for certain special cases)
[ ] exchange-correlation energy density (wish list; perhaps far off except for certain special cases)
[ ] fitting coefficients/exponents for Slaters to the density
[ ] fitting coefficients/exponents for MBIS to the density
[ ] fitting coefficients/exponents for Gaussians to the density
It isn't really part of AtomDB per se, but when multiple entries for a data entry are there, we should default to experiment or the highest-accuracy HCI (or similar) calculation we have. That way a user doesn't necessarily have to request a specific piece of data.
gabrielasd
commented
1 year ago
Properties in AtomDB
This file lists the properties in AtomDB, together with their format. For any of these properties, a "promolecular" value should be possible to define. It will generally be either a mean (perhaps a geometric mean or an l-infinity mean) or a sum of the atomic properties.
Scalars:
Given the atomic number, charge (default to zero), multiplicity (default to ground state of species with that charge and multiplicity), and excitation-level (default to lowest-energy state for a given charge and multiplicity). When fractional charge/multiplicity is provided, the correct thing to do is to define the value from the convex hull. Fractional excitation is not something I know how to support, except perhaps when the fractional occupation is less than one.
Vectors:
It isn't really part of AtomDB per se, but when multiple entries for a data entry are there, we should default to experiment or the highest-accuracy HCI (or similar) calculation we have. That way a user doesn't necessarily have to request a specific piece of data.
Originally posted by @PaulWAyers in https://github.com/QuantumElephant/atomdb/issues/2#issuecomment-812965031