## Hartree atomic units |

the

**hartree atomic units**are a ofsystem of measurement which is especially convenient fornatural units calculations. they are named after the physicistatomic physics .douglas hartree ^{[1]}in this system the numerical values of the following four fundamental are all unity by definition:physical constants , also known as theelectron mass **atomic unit of mass**^{[2]}^{[3]} , also known as theelementary charge **atomic unit of charge**^{[4]} , also known as thereduced planck constant **atomic unit of action**^{[5]} , also known as thevacuum permittivity **atomic unit of permittivity**^{[6]} , also known as theboltzmann constant **atomic unit of heat capacity**

in hartree atomic units, the

is approximately 137.036 atomic units of speed. atomic units are often abbreviated "a.u." or "au", not to be confused with the same abbreviation used also forspeed of light ,astronomical units , andarbitrary units in other contexts.absorbance units - use and notation
- defining constants
- units
- physical constants
- bohr model in atomic units
- non-relativistic quantum mechanics in atomic units
- comparison with planck units
- see also
- notes and references
- external links

The **Hartree atomic units** are a ^{[1]} In this system the numerical values of the following four fundamental

Electron mass , also known as the**atomic unit of mass**^{[2]}^{[3]}Elementary charge , also known as the**atomic unit of charge**^{[4]}Reduced Planck constant , also known as the**atomic unit of action**^{[5]}Vacuum permittivity , also known as the**atomic unit of permittivity**^{[6]}Boltzmann constant , also known as the**atomic unit of heat capacity**

In Hartree atomic units, the