lifetime broadening 

https://doi.org/10.1351/goldbook.08632
Homogeneous line-broadening due to the limited lifetime of energy states involved in a transition.
Note:
The lifetime may be limited by the natural lifetime, by collisions, as in pressure broadening, or by anharmonic vibrational interactions as in phonon-phonon collisions in solids.
Source:
PAC, 2021, 93, 647. (Glossary of methods and terms used in analytical spectroscopy (IUPAC Recommendations 2019)) on page 753 [Terms] [Paper]