All Problems

Properties of Atoms. Spectra.

Problem 6.132

The wavelength of a resonant mercury line is \(\lambda=\) \(=253.65 \mathrm{nm}\). The mean lifetime of mercury atoms in the state of resonance excitation is \(\tau=0.15\) \mus. Evaluate the ratio of the Doppler line broadening to the natural linewidth at a gas temperature \(T=300 \mathrm{~K}\).

Reveal Answer
ΔλDop/Δλnat4πτvpr/λ103, where vpr=2RT/M\Delta \lambda_{D o p} / \Delta \lambda_{n a t} \approx 4 \pi \tau v_{p r} / \lambda \approx 10^{3}, \text { where } v_{p r}=\sqrt{2 R T / M}