qspec.p_e  (  e ,  m ,  p0 = 0 ,  relativistic = True  )[source]

The momentum $p = \frac{1}{c}\sqrt{E^2 + (p_0 c)^2 + 2E\sqrt{(p_0 c)^2 + (mc^2)^2}}$.

Parameters:

earray_like

The energy $E$ added to the kinetic energy of a body with momentum p0 (eV).

marray_like

The mass $m$ of the body (u).

p0array_like

The initial momentum of the body (u m/s).

relativisticbool

The calculation is performed either relativistically (True) or classically (False). The default is True.

Returns:

pndarray

The momentum $p$ of a body with mass m and starting momentum p0 after the addition of the energy e (u m/s).