iNSE ToyBox

Neutron wavelength-velocity-energy relation
Wavelength [Å]	Velocity [m/s]	Energy [eV]



Velocity [m/s]	Wavelength [Å]	Energy [eV]


Energy [eV]	Wavelength [Å]	Velocity [m/s]

Example: Wavelenght = 1.8 Å ⇔ Velocity = 2200 m/s ⇔ Energy = 0.025 eV.

Formulae
Wavelength [Å]	Velocity [m/s]	Energy [eV]

$λ$	$v = \frac{3956.034011}{λ}$	$E = \frac{0.08180421031}{λ^{2}}$

Velocity [m/s]	Wavelength [Å]	Energy [eV]
$v$	$λ = \frac{3956.034011}{v}$	$E = 5.227037589E-9 v^{2}$

Energy [eV]	Wavelength [Å]	Velocity [m/s]
$E$	$λ = \frac{0.2860143533}{\sqrt{E}}$	$v = 13831.59259 \sqrt{E}$

CODATA Internationally recommended 2018 values https://physics.nist.gov/cuu/Constants/

Speed of light in vacuum: c = 299 792 458 m s^-1

Reduced Planck constant times c in MeV fm: hbar c = 197.326 980 4 MeV fm

Neutron mass energy equivalent in MeV: mc^2 = 939.565 420 52 MeV
(Standard uncertainty: 0.000 000 54 MeV)