Fr.: élargissement de raie
A widening of → spectral lines due to any of several factors, including the → Doppler broadening, → instrumental broadening, → microturbulence, → pressure broadening, → rotational broadening, the → Stark effect, and the → Zeeman effect.
natural line broadening
pahneš-e zâstâri-ye xatt
Fr.: élargissement naturel de raie
The broadening of any spectral line due to the fact that excited levels have mean lives, which, by virtue of the uncertainty principle, implies a spread in the energy values.