APClite.jl

A lightweight version of AtomicAndPhysicalConstants.jl that provides atomic and physical constants as plain Float64 values in fixed units.

Features

• Latest CODATA 2022 data: All physical constants from the most recent CODATA release
• No dependencies: Pure Julia with no external dependencies
• Fast compilation: Simple static constants for optimal performance
• Simple API: Easy-to-use Species struct with direct field access
• Comprehensive coverage: Subatomic particles, atoms, ions, and isotopes
• Robust parsing: Efficient atomic name parser with comprehensive error handling

Comparison with AtomicAndPhysicalConstants.jl

Feature	APClite	AtomicAndPhysicalConstants
Dependencies	None	Unitful, DynamicQuantities, etc.
Performance	Fast	Slower
Units	Plain Float64	Unitful quantities
Data sources	CODATA 2022 only	Multiple years available
API	Direct field access	Macro-based API

Installation

julia> using Pkg
julia> Pkg.add(url="https://github.com/ndwang/APClite")

Quick Start

using APClite

# Access physical constants directly
C_LIGHT          # 2.99792458e8 [m/s]
H_PLANCK         # 6.62607015e-34 [J⋅s]
M_ELECTRON       # 510998.95069 [eV/c²]
FINE_STRUCTURE   # 0.0072973525643

# Create species objects
e = Species("electron")
p = Species("proton")
h = Species("H")
h_ion = Species("H+")
anti_p = Species("anti-proton")

# Access species properties (direct fields)
e.mass           # 510998.95069 [eV/c²]
p.charge         # 1.0 [e]
e.spin           # 0.5 [ħ]
e.g_factor       # g-factor (dimensionless)

Supported Species

Subatomic Particles

• "electron", "positron"
• "proton", "anti-proton"
• "neutron", "anti-neutron"
• "muon", "anti-muon"
• "pion0", "pion+", "pion-"
• "deuteron", "anti-deuteron"
• "photon"

Atomic Species

• Supported elements from "H" to "Og"

Mass Number Format (optional)

• Mass number before the atomic symbol
• Optional "#" symbol at the beginning
• If not specified, uses the average of the mass in naturally occurring samples.

julia> Species("12C")
julia> Species("#12C")

Charge Format (optional)

• Charge number after the atomic symbol
  • "+" - Single positive charge (e.g., "C+")
  • "++" - Double positive charge (e.g., "C++")
  • "+n" - n positive charges (e.g., "C+3")
  • "n+" - n positive charges (e.g., "C3+")
  • "-" - Single negative charge (e.g., "C-")
  • "--" - Double negative charge (e.g., "C--")
  • "-n" - n negative charges (e.g., "C-2")
  • "n-" - n negative charges (e.g., "C2-")

API Reference

Constants

All constants are available as module-level constants, grouped by type:

• Fundamental constants

  • C_LIGHT: Speed of light [m/s]
  • H_PLANCK: Planck constant [J⋅s]
  • H_BAR: Reduced Planck constant [J⋅s]
  • E_CHARGE: Elementary charge [C]
  • FINE_STRUCTURE: Fine structure constant (dimensionless)
  • AVOGADRO: Avogadro constant [mol⁻¹]
  • R_ELECTRON: Classical electron radius [m]
  • R_PROTON: Classical proton radius [m]
  • EPS_0: Permittivity of free space [F/m]
  • MU_0: Permeability of free space [N/A²]

• Particle masses [eV/c²]

  • M_ELECTRON: Electron
  • M_PROTON: Proton
  • M_NEUTRON: Neutron
  • M_MUON: Muon
  • M_PION_0: Neutral pion
  • M_PION_CHARGED: Charged pion
  • M_DEUTERON: Deuteron
  • M_HELION: Helion (³He nucleus)

• Magnetic moments [J/T]

  • MU_ELECTRON: Electron
  • MU_PROTON: Proton
  • MU_NEUTRON: Neutron
  • MU_MUON: Muon
  • MU_DEUTERON: Deuteron
  • MU_HELION: Helion
  • MU_TRITON: Triton

• g-factors (dimensionless)

  • G_ELECTRON: Electron
  • G_PROTON: Proton
  • G_NEUTRON: Neutron
  • G_MUON: Muon
  • G_DEUTERON: Deuteron
  • G_HELION: Helion
  • G_TRITON: Triton

• Magnetic moment anomalies (dimensionless)

  • ANOMALY_ELECTRON: Electron
  • ANOMALY_MUON: Muon

• Unit conversions

  • KG_PER_AMU: Kilograms per atomic mass unit [kg/amu]
  • EV_PER_AMU: Electronvolts per atomic mass unit [eV/amu]
  • J_PER_EV: Joules per electronvolt [J/eV]
  • C_PER_E: Coulombs per elementary charge [C/e]

• Release info

  • RELEASE_YEAR: Data release year

Species

• Species(name::String): Create a species from name
• Access fields directly:
  • species.mass (eV/c²)
  • species.charge (units of e)
  • species.spin (ħ)
  • species.moment (J/T)
  • species.g_factor (dimensionless)
  • species.iso (mass number)
  • species.kind (ATOM, HADRON, LEPTON, PHOTON, NULL)
  • species.name or nameof(species) for isotope and charge information

Examples

using APClite

# Physical constants
println("Speed of light: ", C_LIGHT, " m/s")
println("Electron mass: ", M_ELECTRON, " eV/c²")

# Create particles
electron = Species("electron")
proton = Species("proton")
hydrogen = Species("H")
carbon12 = Species("12C")

# Access properties
println("Electron charge: ", electron.charge, " e")
println("Proton mass: ", proton.mass, " eV/c²")
println("Hydrogen mass: ", hydrogen.mass, " eV/c²")

# Display species
println(electron)
println(proton)

Custom species

using APClite

# 1) Direct construction (no registry entry needed)
#    name, charge [e], mass [eV/c^2], spin [ħ], moment [J/T], g_factor, iso, kind
custom = Species("my-hadron", 1.0, 2.5e9, 0.5, 0.0, 2.0, 0.0, HADRON)
println(custom)

# 2) Register a custom subatomic species for name-based construction
APClite.SUBATOMIC_SPECIES["X-"] = (
    charge=-1.0,
    mass=1e9.0,
    spin=0.5,
    moment=0.0,
    kind=HADRON,
)
xminus = Species("X-")
println(xminus)

# 3) Register a custom atomic element (with isotopes) for name/ion/isotope parsing
APClite.ATOMIC_SPECIES["Xe"] = (
    Z=54,
    isotopes=Dict(129 => 120000.0, 132 => 122000.0, -1 => 121000.0),
)
xe129pp = Species("129Xe++")
println(xe129pp)