Skip to content

Constants

Navigation:

Valid Identifiers for Constants

In all tables, the valid identifiers for units that can be used in TOP-Energy are highlighted in bold type.

Mathematics

Constant Identifier (name) Definition
Pi 𝜋 (Archimedes’ constant) PI 3,14159265358979323846

Light and Sound

Constant Identifier (symbol) Comment Definition
Speed of light c measured in vacuum 2,99792458·108 m/s
Speed of sound mach in dry air under standard conditions 331,46 m/s

Standard State Conditions

Constant Identifier (name) Identifier (symbol) Definition
Standard temperature standardtemp stdtemp 273.15 K
Standard pressure atmosphere atm 101325 Pa

Particle Physics

Constant Identifier (name) Identifier (symbol) Comment Definition
Gravitational constant gravity force constant of proportionality in the law of gravity 9,80665 m/s2
Planck constant h_planck 6,62606876·10-34 J s
Reduced Planck constant h_bar h_planck/2 PI
Elementary charge e 1,602176462·10-19 C
Electron volt eV increase in the kinetic energy of an electron at an acceleration voltage of 1 volt 1 e V
Atomic mass unit atomicmassunit amu
u
one twelfth of the mass of 12C 1,66053873·10-27 kg
Chemical atomic mass unit amu_chem one sixteenth of the average mass of oxygen in the natural isotope mixture 1,66026·10-27 kg
Physical atomic mass unit amu_phys one sixteenth of the mass of the oxygen isotope 16O 1,65981·10-27 kg
Dalton dalton common term for the atomic mass unit in biochemistry 1 u
Electron mass electronmass m_e 5,48579911·10-4 u
Proton mass protonmass m_p 1,00727646688 u
Neutron mass neutronmass m_n 1,00866491578 u
Muon mass muonmass m_mu 0,1134289168 u
Deuteron mass deuteronmass m_d 2,01355321271 u
Alpha particle mass alphaparticlemass m_alpha 4,0015061747 u

Chemistry

Constant Identifier (name) Identifier (symbol) Comment Definition
Avogadro constant avogadro N_A number of particles per amount of substance 1 gram/amu mol
Gas constant gasconstant R 8,314472 J/mol K
Boltzmann constant boltzmann k 1 R/N_A
Mole volume molarvolume volume of one mole of an ideal gas under standard conditions 1 mol R stdtemp/atm
Loschmidt constant loschmidt number of molecules per volume unit of an ideal gas under standard conditions 1 avogadro mol/molarvolume
Stefan–Boltzmann constant stefanboltzmann constant of proportionality in the Stefan–Boltzmann law (describes the power radiated from a black body in terms of its temperature) PI2 K4/60 hbar3 c2
Back To Top