When an alkali metal dissolves in liquid ammonia, die solution acquires different colours. Explain the reasons for this type of colour change

All alkali metals dissolve in liquid ammonia giving highly conducting deep blue solutions.

(i) When ordinary light falls on these ammoniated
electrons, they get excited and jump to higher energy levels by asborbing energy correspond-ing to red region of the visible light. As a result, transmitted light is blue which imparts blue colour to the solution.
(ii) Dilute solutions of alkali metals in liquid ammonia are dark blue in colour, but as the concentration increases above 3M, the colour changes to copper-bronze and the solutions acquire metallic lustre due to the formation of metal ion clusters.