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Properties of Atoms. Spectra.

Problem 6.132

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

Reveal Answer
ΔλDop/Δλnat≈4πτvpr/λ≈103, 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}
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