Observation of an excimer emission band of the ArOD van der Waals molecule

Abstract

An excimer emission band attributed to a transition from the first excited state to the ground state of the van der Waals Ar(OO) molecule has been observed in experiments where 0 2 0 was dissociated in presence of rare gases by two photons of a quadrupled Y AG laser (266 nm). KrOO has also been observed in the same experiments. The ArOO excimer band comprises three main peaks at 313.9, 315.1, and 316.0 nm as well as several minor ones nearer to the main OH (A2~ + ,v = O-Xln,v = 0) emission band. The emission profile is realistically simulated by a one dimension model using recently published potentials for the excited state and modeling the ground state by that of the ArF X 2~ + state. This result tends to demonstrate that the ground state geometry of Ar(OO) involved in the transition is probably L shaped although the high intensity of the observed excimer band is not satisfactorily explained.

Impact of Ultrasonic Frequency on Aqueous Sonoluminescence and Sonochemistry

“…These excimers are formed by three-body collisions and emit at λ < 300 nm . This process occurs at short distances between H 2 O* and M, where the collisional potential is equal to or greater than thermal energy, because, in this situation, a third species may remove the excess kinetic energy of H 2 O and M. In the presence of argon, the only inert species in our system, Ar • OH* (λ ∼ 310, 316, and 318 nm) and Ar • HO* (λ ∼ 340 nm) excimers, can exist: …”

“…These excimers are formed by three-body collisions and emit at λ < 300 nm. 28 This process occurs at short distances between H 2 O* and M, where the collisional potential is equal to or greater than thermal energy, because, in this situation, a third species may remove the excess kinetic energy of H 2 O and M. In the presence of argon, the only inert species in our system, Ar • OH* (λ ∼ 310, 316, and 318 nm) and Ar • HO* (λ ∼ 340 nm) excimers, can exist: 29 The spectral features at different frequencies (Figure 2) indicate that the fundamental mechanisms of SL are similar during irradiation with any of the frequencies in this study. Since SL is known to originate from the gas phase and not from the interface or bulk solution, bubble implosion at 205, 358, and 618 kHz provides energetically favorable conditions for luminescent type reactions.…”