chemart hub

chemart / nuclear-reaction-networks

View on GitHub

Nuclear reaction networks — Real nuclear physics in the same record as the artificial chemistries, which makes it an unusually good validation target. Nuclides and elementary particles are the species, fusion and decay the reactions, and measured c…

chemistry official · built in non-chemical fidelity: book+decisions #banzhaf-yamamoto

How it works

Real nuclear physics in the same record as the artificial chemistries, which makes it an unusually good validation target. Nuclides and elementary particles are the species, fusion and decay the reactions, and measured cross-section libraries exist to check against. The CNO cycle is also a textbook catalytic organisation: carbon, nitrogen and oxygen are consumed and regenerated while hydrogen is converted to helium, so the catalysts appear on both sides and would vanish from a net stoichiometric matrix.

S
nuclides and elementary particles (n, 1H, 2H, ..., e+, e-, nu_e, gamma) · explicit
R
e.g. 1H + 1H -> 2H + e+ + nu_e. The CNO cycle is a genuine CATALYTIC cycle: 12C + 1H -> 13N + gamma ; 13N -> 13C + e+ + nu_e ; 13C + 1H -> 14N + gamma ; 14N + 1H -> 15O + gamma ; 15O -> 15N + e+ + nu_e ; 15N + 1H -> 12C + 4He. · arity 1, 2
A
ode · open: 1H flows in, 4He, e+, nu_e flow out

Parameters

namedefaultmeaning
network
enum · structural
 "cno-cycle" which reaction network to generate
cno-cycle | pp-chain | big-bang-nucleosynthesis

Nuclear reaction networks

One of the artificial chemistries of Banzhaf & Yamamoto, Artificial Chemistries (MIT Press, 2015), §20.2.

Its generator ships with the chemart library, so loading it runs no code from the hub and needs no trust_remote_code.

import chemart

net = chemart.generate_network("chemart/nuclear-reaction-networks", seed=0)   # same as "nuclear-reaction-networks"
print(net.summary())

What to look for

  • the CNO cycle is a closed, self-maintaining organisation with C, N, O as catalysts
  • observed light-element abundances from big-bang nucleosynthesis

Implementation decisions

  • Topology only. Rates depend on temperature and density through cross sections (e.g. REACLIB), which the book does not give, so cross_sections, temperature and density are not parameters.
  • cno-cycle is book eq. 20.4, with the book's open boundary (1H in; 4He, e+, nu_e out) recorded in extras.boundary rather than as numeric flows. pp-chain is eq. 20.3 completed with the standard pp-I branch. big-bang-nucleosynthesis is the standard 12-reaction network among n, 1H, 2H, 3H, 3He, 4He, 7Li, 7Be, standing in for figure 20.4, which only draws the network.
  • extras.conservation lists baryon number, charge (fully ionised nuclei) and electron lepton number, all exact.

Banzhaf & Yamamoto, Artificial Chemistries (2015), §20.2

Preview at default parameters

11 species · 6 reactions · status complete · seed 1

12C + 1H -> 13N + gamma
13N -> 13C + e+ + nu_e
13C + 1H -> 14N + gamma
14N + 1H -> 15O + gamma
15O -> 15N + e+ + nu_e
15N + 1H -> 12C + 4He

Generated by the uploader with chemart push; the hub never runs uploaded code.