Electron attachment and dynamics of alkali atoms in<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msub><mml:mrow><mml:mi mathvariant="normal">Al</mml:mi></mml:mrow><mml:mrow><mml:mn>13</mml:mn></mml:mrow></mml:msub></mml:mrow><mml:mi>X</mml:mi></mml:math><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mo>(</mml:mo><mml:mi>X</mml:mi><mml:mo>=</mml:mo><mml:mi mathvariant="normal">Li</mml:mi><mml:mo>–</mml:mo><mml:mi mathvariant="normal">Cs</mml:mi><mml:mo>)</mml:mo></mml:math>clusters

Theoretical electronic structure studies on the anionic and neutral ${\mathrm{Al}}_{13}X$ $(X=\mathrm{Li}--\mathrm{Cs})$ clusters have been carried out using a gradient corrected density-functional approach. The alkali atoms occupy the hollow sites on the ${\mathrm{Al}}_{13}$ icosahedron surface and the calculated vertical transition energies from the ground state of the anions to various neutral states are found to be close to the recent preliminary experimental data. A detailed investigation of the Born-Oppenheimer surface of ${\mathrm{Al}}_{13}\mathrm{K}$ shows that the minimum energy path for the motion of K atoms to the neighboring hollow sites passes through a bridge site and has a barrier of 0.13 eV. If energy could be imparted that will enable the K atoms to overcome the barrier and slide freely on the surface, the cluster will exhibit a small orbital magnetic moment that could be observed at low temperatures.