hydrogen.py 文件源码

def 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

    """
    n, Z = S(n), S(Z)
    if n.is_integer and (n < 1):
        raise ValueError("'n' must be positive integer")
    return -Z**2/(2*n**2)