In: Physics
Doubly ionized lithium Li2+ (Z = 3) and triply ionized beryllium Be3+ (Z = 4) each emit a line spectrum. For a certain series of lines in the lithium spectrum, the shortest wavelength is 40.5 nm. For the same series of lines in the beryllium spectrum, what is the shortest wavelength?
The emission (or absorption spectra) of H-like atoms is given by the Rydberg formula as
where R = Rydbergs constant
nf = principal quantum number of the level to which transition is made.
ni = principal quantum number of the level from which transition is made.
= wavelength of photon emitted(or absorbed).
For a particular series, nf is fixed while as ni changes. Shortest wavelength for a particular series corresponds to ni = . So, for the shortest wavelength of a series
So