title: Far-infrared amplified spontaneous emission and collisional energy transfer between the E 0(g)⁺ (³P₂) and D 0(u)⁺ (³P₂) ion-pair states of I₂.
abstract: We report direct observation of far-infrared amplified spontaneous emission from the E 0(g)⁺ ((3)P2) (v(E) = 0 - 3) ion-pair state of I2 by using an optical-optical double resonance technique with the B (3)Πu (0(u)⁺) (v(B) = 19) valence state as the intermediate state. The directional far-infrared emission detected in the wavelength range from 19 to 28 μm was assigned to the vibronic transitions from the E 0(g)⁺ ((3)P2) ion-pair state to the D 0(u)⁺ ((3)P2) ion-pair state. The subsequent UV fluorescence from the D 0(u)⁺ ((3)P2) state was also observed, which consists not only from the vibrational levels populated by the amplified spontaneous emission but also from those populated by collisional energy transfer. Analyses of the vibrational distribution in the D 0(u)⁺ ((3)P2) state revealed that the population transfer through the amplified spontaneous emission was dominant under our experimental conditions.
authors.affiliation: Graduate School of Chemical Sciences and Technology, Tokyo University of Science, 1-3 Kagurazaka, Shinjuku, Tokyo 162-8601, Japan.
authors.forename: Shoma
authors.initials: S
authors.lastname: Hoshino
authors.affiliation: Graduate School of Chemical Sciences and Technology, Tokyo University of Science, 1-3 Kagurazaka, Shinjuku, Tokyo 162-8601, Japan.
authors.forename: Mitsunori
authors.initials: M
authors.lastname: Araki
authors.affiliation: Graduate School of Chemical Sciences and Technology, Tokyo University of Science, 1-3 Kagurazaka, Shinjuku, Tokyo 162-8601, Japan.
authors.forename: Koichi
authors.initials: K
authors.lastname: Tsukiyama