Hydrogen Wavefunctions

sympy.physics.hydrogen.E_nl(n, Z=1)

Returns the energy of the state (n, l) in Hartree atomic units.

The energy doesn’t depend on “l”.

Examples

>>> from sympy import var
>>> from sympy.physics.hydrogen import E_nl
>>> var("n Z")
(n, Z)
>>> E_nl(n, Z)
-Z**2/(2*n**2)
>>> E_nl(1)
-1/2
>>> E_nl(2)
-1/8
>>> E_nl(3)
-1/18
>>> E_nl(3, 47)
-2209/18

sympy.physics.hydrogen.E_nl_dirac(n, l, spin_up=True, Z=1, c=137.035999037000)

Returns the relativistic energy of the state (n, l, spin) in Hartree atomic units.

The energy is calculated from the Dirac equation. The rest mass energy is not included.

n, l

quantum numbers ‘n’ and ‘l’

spin_up

True if the electron spin is up (default), otherwise down

Z

atomic number (1 for Hydrogen, 2 for Helium, ...)

c

speed of light in atomic units. Default value is 137.035999037, taken from: http://arxiv.org/abs/1012.3627

Examples

>>> from sympy.physics.hydrogen import E_nl_dirac
>>> E_nl_dirac(1, 0)
-0.500006656595360

>>> E_nl_dirac(2, 0)
-0.125002080189006
>>> E_nl_dirac(2, 1)
-0.125000416028342
>>> E_nl_dirac(2, 1, False)
-0.125002080189006

>>> E_nl_dirac(3, 0)
-0.0555562951740285
>>> E_nl_dirac(3, 1)
-0.0555558020932949
>>> E_nl_dirac(3, 1, False)
-0.0555562951740285
>>> E_nl_dirac(3, 2)
-0.0555556377366884
>>> E_nl_dirac(3, 2, False)
-0.0555558020932949

sympy.physics.hydrogen.R_nl(n, l, r, Z=1)

Returns the Hydrogen radial wavefunction R_{nl}.

n, l

quantum numbers ‘n’ and ‘l’

r

radial coordinate

Z

atomic number (1 for Hydrogen, 2 for Helium, ...)

Everything is in Hartree atomic units.

Examples

>>> from sympy.physics.hydrogen import R_nl
>>> from sympy import var
>>> var("r Z")
(r, Z)
>>> R_nl(1, 0, r, Z)
2*sqrt(Z**3)*exp(-Z*r)
>>> R_nl(2, 0, r, Z)
sqrt(2)*(-Z*r + 2)*sqrt(Z**3)*exp(-Z*r/2)/4
>>> R_nl(2, 1, r, Z)
sqrt(6)*Z*r*sqrt(Z**3)*exp(-Z*r/2)/12

For Hydrogen atom, you can just use the default value of Z=1:

>>> R_nl(1, 0, r)
2*exp(-r)
>>> R_nl(2, 0, r)
sqrt(2)*(-r + 2)*exp(-r/2)/4
>>> R_nl(3, 0, r)
2*sqrt(3)*(2*r**2/9 - 2*r + 3)*exp(-r/3)/27

For Silver atom, you would use Z=47:

>>> R_nl(1, 0, r, Z=47)
94*sqrt(47)*exp(-47*r)
>>> R_nl(2, 0, r, Z=47)
47*sqrt(94)*(-47*r + 2)*exp(-47*r/2)/4
>>> R_nl(3, 0, r, Z=47)
94*sqrt(141)*(4418*r**2/9 - 94*r + 3)*exp(-47*r/3)/27

The normalization of the radial wavefunction is:

>>> from sympy import integrate, oo
>>> integrate(R_nl(1, 0, r)**2 * r**2, (r, 0, oo))
1
>>> integrate(R_nl(2, 0, r)**2 * r**2, (r, 0, oo))
1
>>> integrate(R_nl(2, 1, r)**2 * r**2, (r, 0, oo))
1

It holds for any atomic number:

>>> integrate(R_nl(1, 0, r, Z=2)**2 * r**2, (r, 0, oo))
1
>>> integrate(R_nl(2, 0, r, Z=3)**2 * r**2, (r, 0, oo))
1
>>> integrate(R_nl(2, 1, r, Z=4)**2 * r**2, (r, 0, oo))
1