# arc.calculations_atom_single.DynamicPolarizability.getPolarizability#

Calculates of scalar, vector, tensor, core and pondermotive polarizability, and returns state corresponding to the closest transition resonance.

Note that pondermotive polarisability is calculated as $$\alpha_P = e^2 / (2 m_e \omega^2)$$, i.e. assumes that the definition of the energy shift in field $$E$$ is $$\frac{1}{2}\alpha_P E^2$$. For more datils check the preprint arXiv:2007.12016 that introduced the update.

Parameters
• driveWavelength (float) – wavelength of driving field (in units of m)

• units (string) – optional, ‘SI’ or ‘a.u.’ (equivalently ‘au’), switches between SI units for returned result ($$Hz V^{-2} m^2$$ ) and atomic units (”$$a_0^3$$ “). Defaul ‘SI’

• accountForStateLifetime (bool) – optional, should we account for finite transition linewidths caused by finite state lifetimes. By default False.

Returns

scalar, vector, and tensor, polarizabilities of the state specified, as well as the core, and ponderomotive polarizabilities of the atom, followed by the atomic state whose resonance is closest in energy. Returned units depend on units parameter (default SI).