The visible afterglow radiation from lowhyphen;pressure weakly ionized helium exhibits a partial quenching due to absorption of infrared photons (0.11ndash;0.14 eV). The helium sample is placed in the cavity of aQhyphen;switched CO2laser and studied at gas temperatures in the range from 77 to 300deg;K. The partial quenching appears to originate from photonhyphen;induced change of population of a state or states of a neutral or ionic helium molecule.
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