NIST Physical constant (2018)
SI Units

Clear["Global`*"];rule1={me->9.109383701528 (10^(-31)),qe->1.602176634 (10^(-19)),ge->2.00231930436256,kB->1.380649 (10^(-23)), c->2.99792458 (10^8), ϵ0->8.8541878128 (10^(-12)),μ0->1.25663706212 (10^(-6)), α->7.2973525693 (10^(-3)),u->1.66053906660 (10^(-27)),mp->1.67262192369 (10^(-27)),mn->1.6749274980495 (10^(-27)),  rB->5.29177210903 (10^(-11)), μB->9.274010078328 (10^(-24)),μN->5.0507837461 (10^(-27)),   h->6.62607015 (10^(-34)), ℏ->1.054571817 (10^(-34)),λc->2.42631023867 (10^(-12)),eV->1.602176634 (10^(-19)),MeV->1.602176634 (10^(-13)),Ry->13.605693122994 eV, σSB->5.670374419 (10^(-8)), z0->376.73031366857, Φ0->2.067833848 (10^(-15)),Rk->25812.80745, Mea->5.9736 (10^24), Rea->6.3781   (10^6) , Msun->1.98847 (10^30), Rsun->6.9570 (10^8),Mmoon->7.3483 (10^22), ly->9.4607 (10^15), pc->3.0857   (10^16), AU->1.495978707  (10^11),mile->1.609344 (10^3), hour->3600, fm->(10^(-15)), nm->(10^(-9)), Å->(10^(-10)),NA->6.02214076 (10^23),R->8.314462618, cal->4.184, atm->101325 , g->9.80665,G->6.6743015  (10^(-11))};

me:		Mass of electron			(kg)
qe:		Electron charge			(C)
ge:		g-factor of electron			
kB:		Boltzmann constant		(J/K)
c:		Speed of light in vacuum		(m/s)
ϵ0:		Permittivity of free space	((C^2)/(N (m^2))
μ0:		Permeability of free space	(kgm/(C^2))
α:		Fine structure constant
u:		Atomic unit mass			(kg)
mp:		Mass of proton				(kg)
mn:		Mass of neutron			(kg)
rB:		Bohr radius				(m)
μB:		Bohr magneton			(J/T)	
μN:		Nuclear magneton			(J/T)	
 ℏ:		Dirac constant				(Js)
 h:		Planck constant			(J s)
 λc:		Compton wavelength		(m)	

		

		



			
Ry:		Rydberg constant			(J)
σSB:		Stefan-Boltzmann constant	(W/((m^2)(K^4)))	
z0:		Impedance of free space		(Ω)
Φ0:		Magnetic flux quantum		(Wb=T (m^2))
RK:		von Klitzing constant		(Ω)
fm 		= (10^(-15)) m
1 Å		=(10^(-10)) m
cal:		Calorie					(J)
atm:		Atmosphere				(Pa=N/(m^2))
NA:		Avogadro’s number 		((mole^(-1)))
G:		Gravitational constant		(N (m^2)/(kg^2))
g:		acceleration of gravity		(m/(s^2))
Mmoon: 	Mass of moon 				(kg)
Rsun:	Radius of sun 				(m)
Mea:		Mass of earth				(kg)
Rea:		radius of earth				(m)
Msun:	Mass of sun				(kg)
pc:		parsec					(m)			
ly: 		light year					(m)
AU: 		Astronomical unit			(m)

Fine structure constant

(1/(4 π ϵ0)) ((qe^2)/(ℏ c)) //.rule1//ScientificForm

((%)^(-1))

Bohr radius

((4 π ϵ0 (ℏ^2))/((qe^2)me Å)) //.rule1

NumberForm[%,16]

Hydrogen atom ground state energy

-(1/2)((me (c^2) (α^2))/eV)//.rule1

NumberForm[%,16]

Magnetic flux quantum

((2 π ℏ)/(2 qe))//.rule1

NumberForm[%,16]