Temari¶
Atomic scattering and excitation factors from first principles.
Temari solves an isolated atom from scratch — self-consistent field, bound orbitals, distorted continuum waves — and derives the scattering and excitation factors that electron microscopy, spectroscopy and transport simulation need. No external atomic-structure code, no fitted parameter tables, no dependencies beyond the Julia standard library.
The name
Temari (手毬) is a traditional Japanese craft: a sphere divided geometrically, then wound with many threads to form a pattern. That is what this code does — it lays dozens of partial waves over a spherically symmetric atomic field. The partial-wave skeleton is the same whether the exit is an ionization form factor, a generalized oscillator strength, or an elastic phase shift.
Status: early
The engine exists and is in production use — it generates the STEM-EDX ionization tables shipped with ReciPro. It is split into the L0–L5 layer files, and six exits now sit on top of it: \(F(s, E_0)\), the EELS edge \(\mathrm{d}\sigma/\mathrm{d}\Delta E\), the generalized oscillator strength, elastic phase shifts, Mott elastic scattering, and atomic scattering factors. The repository is being assembled around them.
What it computes today¶
One engine, six exits. Everything below comes from the same self-consistent atom, the same relativistic bound orbitals and the same distorted continuum waves — they differ only in the operator and in what is reported.
| Exit | Quantity | Command |
|---|---|---|
| Ionization form factor | \(F(s, E_0)\) for K, L1–L3 and M1–M5, plus \(\sigma(E_0)\) from the Bote–Salvat coefficients | <Z> <channel> <E0> |
| EELS core-loss edge | \(\mathrm{d}\sigma/\mathrm{d}\Delta E\) and the inner-shell contribution to the stopping power | edge |
| Generalized oscillator strength | \(\mathrm{d}f/\mathrm{d}\Delta E(Q)\), the Bethe surface — independent of \(E_0\) | gos |
| Elastic phase shifts | \(\delta_l\) in the neutral atom's static field | phase |
| Mott elastic scattering | \(\mathrm{d}\sigma/\mathrm{d}\Omega\), \(\sigma_{el}\), \(\sigma_{tr}\) and the Sherman function | mott |
| Atomic scattering factors | \(f_x(s)\) for X-rays and \(f_e(s)\) for electrons, from the SCF density — first principles instead of a fitted table | fx |
The form factor is normalized to \(F(0) = 1\) and carries the delocalization of the inelastic image; the absolute scale is supplied by the cross section. See The physics for the prescription and its known limits, and the command-line reference for what each exit reports.
Find by goal¶
| Goal | Start here |
|---|---|
| Run it once and see a number | Getting started |
| Every subcommand and flag | Command-line reference |
| What prescription is actually implemented | The physics |
| Where a new quantity would be plugged in | Architecture |
| How far the numbers are trusted, and why | Verification |
| Why an obvious optimization was rejected | Reproducibility, Performance |
| What is planned, and what is deliberately out of scope | Roadmap |
| A long batch stopped making progress on Windows | Troubleshooting |
Why this exists¶
The physics of an isolated atom scattering a fast electron, a photon, or another electron is one calculation with several exits. Existing open tools each expose one exit and hide the engine:
- Ionization form factors for STEM-EDX / EELS mapping are locked inside microscopy simulators.
- The standard EELS generalized oscillator strength (GOS) tables date from the 1980s (Egerton's SIGMAK/SIGMAL, Leapman's Hartree–Slater tables). A modern, open, relativistic GOS table effectively does not exist.
- Elastic scattering phase shifts live in separate Fortran packages.
- Atomic scattering factors are distributed as fitted parameterizations rather than as something you can recompute for an arbitrary ion.
Temari puts the engine in the open and adds exits to it. Three quantities are already computed inside the current call graph and thrown away before returning — exposing them is output plumbing, not physics. See Architecture.
Design commitments¶
- Zero dependencies. Julia standard library only. The sole bundled data file is the Bote–Salvat cross-section coefficient set (public domain).
- Standalone. No
module, no package environment: the layer files carry a flat namespace and concatenate in include order, so it stays possible to hand the whole engine to someone as a single file. - MIT licensed. A reference implementation should be readable and usable.
- Fast, but reproducibility outranks speed: optimizations that change floating-point summation order are adopted only when a full table regeneration is intended, and are declared as such.
- The physics is readable in the source. Comments in the code are the authoritative statement of the prescription.
- The engine/GUI boundary is a CLI contract. Any GUI is a separate process that calls subcommands and reads JSON — never linked in-process.
What is not here¶
- No shipped tables. This repository holds code and documentation. The generated dataset lives with the application that ships it.
- No reference data from restricted sources. Comparison against published tables and GPL-licensed codes is part of development, but those numbers are never copied into this repository.
Credits and licensing¶
MIT. Copyright © 2026 Yusuke SETO.
The implementation was largely written with AI assistance (Anthropic Claude); the choice of physical prescription and all verification are the author's responsibility.
bote_salvat.json is machine-extracted from NIST's BoteSalvatICX.jl (Unlicense,
public domain). If you publish results using the cross sections, please cite
Bote & Salvat, Phys. Rev. A 77 (2008) 042701 and Bote et al., At. Data
Nucl. Data Tables 95 (2009) 871.