Physical constants and isotope data

This section summarizes natural constants available in EasySpin. These include

Fundamental physical constants

EasySpin provides a set of fundamental physical constants that are commonly used in EPR and other areas of spectroscopy and physical chemistry.

Their values are drawn from the CODATA recommended list of fundamental physical constants, which is regularly updated. Every release of EasySpin contains the most up-to-date values available from CODATA at the time of the release.

For each constant, also its uncertainty is available. For example, the value of the Bohr magneton (in J T-1) and its uncertainty can be obtained using bmagn

muB = bmagn;          % just the value
[muB,sigma] = bmagn;  % the value and the uncertainty

The following constants provided by EasySpin are directly relevant to EPR:

gfree g value of the free electron
bmagn Bohr magneton, in J T-1
nmagn nuclear magneton, in J T-1
planck Planck constant, in J s
hbar reduced Planck constant, in J s
mu0 magnetic constant (vacuum permeability), in N A-2

Here is a complete list of available physical constants in EasySpin:

amu Atomic mass unit, in kg
angstrom Angstrom, molecular-scale length unit, in m
avogadro Avogadro number, in mol-1
barn Barn, unit of nuclear electric quadrupole moments, in m2
bmagn Bohr magneton, in J T-1
bohrrad Bohr radius, in m
boltzm Boltzmann constant, in J K-1
clight speed of light in vaccum, in m s-1
echarge elementary electric charge, in C
emass mass of the electron, in kg
eps0 electric constant (vacuum permittivity), in C V-1 m-1
evolt electron volt, in J
faraday Faraday constant, in C mol-1
gfree g factor of the free electron
hartree hartree (atomic unit of energy), in J
hbar reduced Planck constant, in J s
molgas Molar gas constant, in J K-1 mol-1
mu0 magnetic constant (vacuum permeability), in N A-2
nmagn Nuclear magneton, in J T-1
nmass Mass of the neutron, in kg
planck Planck constant, in J s
pmass Mass of the proton, in kg
rydberg Rydberg constant, in m-1
Nuclear isotope data

Data about nuclear isotopes are also available via a set of EasySpin functions and via a graphical interface. If you call isotopes, a user interface will pop up. Alternatively, you can use one of the following functions to access isotope data:

nucabund Natural abundance of nuclear isotopes
nucgval Nuclear g values
nucabund Natural abundance of nuclear isotopes
nucqmom Nuclear quadrupole moments, in barn
nucspin Nuclear spin quantum numbers

Data for all isotopes is included, not just for the magnetic ones. All data are taken directly from the latest primary reference sources (N.J. Stone, Table of Nuclear Magnetic Dipole and Electric Quadrupole Moments; N. E. Holden, Table of the Isotopes, in CRC Handbook of Physics and Chemistry).