# AtomSurfaceVdW#

class AtomSurfaceVdW(atom, surfaceMaterial=None)[source]#

Calculates atom-surface Van der Waals interaction.

Energy of atom state $$|i\rangle$$ at distance $$z$$ from the surface of material is offseted in energy by $$V_{\rm VdW}$$ at small distances $$z\ll\rm{min}(\lambda_{i,j})$$ , where $$\lambda_{i,j}$$ are the wavelengths from atom state $$|i \rangle$$ to all strongly-coupled states $$j$$ , due to (unretarded) atom-surface interaction, also called Van der Waals interaction. The interaction potential can be expressed as

$$V_{\rm VdW} = - \frac{C_3}{z^3}$$

This class calculates $$C_3$$ for individual states $$|i\rangle$$.

See example atom-surface calculation snippet.

Parameters
• atom (AlkaliAtom or DivalentAtom) – specified Alkali or Alkaline Earth atom whose interaction with surface we want to explore

• material (from arc.materials) – specified surface material

Note

To find frequecy shift of a transition $$|\rm a \rangle\rightarrow |\rm b \rangle$$, one needs to calculate difference in $$C_3$$ coefficients obtained for the two states $$|\rm a\rangle$$ and $$|\rm b\rangle$$ respectively. See example TODO (TO-DO)

## Calculate#

 getC3contribution(n1, l1, j1, n2, l2, j2[, s]) Contribution to $$C_3$$ of $$|n_1, \ell_1, j_1\rangle$$ state due to dipole coupling to $$|n_2, \ell_2, j_2\rangle$$ state. getStateC3(n, l, j, coupledStatesList[, s, ...]) Van der Waals atom-surface interaction coefficient for a given state ($$C_3$$ in units of $$\mathrm{J}\cdot\mathrm{m}^3$$ )