XeI((2)pi((1/2))-(2)Sigma((1/2))) excimer emission at 1.3 microm

Area of Science:

• Atomic and Molecular Physics
• Chemical Physics
• Spectroscopy

Background:

• Magnetic dipole transitions are fundamental in atomic spectroscopy.
• Collisional processes can significantly influence atomic transition probabilities.
• Excimer formation plays a role in energy transfer and light emission.

Purpose of the Study:

• To investigate the mechanism of collisional enhancement of the iodine magnetic dipole transition by Xenon.
• To quantify the rate coefficients for the exciplex channel involved in this enhancement.
• To determine the radiative properties of the intermediate Xenon-Iodine (XeI) excimer state.

Main Methods:

• Spectroscopic analysis of the iodine transition at 1.3152 micrometers.
• Collisional studies involving iodine atoms and Xenon gas.
• Kinetic measurements to determine pseudo-first-order and termolecular rate coefficients.
• Estimation of the radiative lifetime of the XeI excimer.

Main Results:

• The collisional enhancement of the iodine transition by Xenon proceeds via an exciplex channel: I(52P1/2) + Xe → XeI(2π1/2) → I(52P3/2) + Xe + hν(1.3 μm).
• The pseudo-first-order rate coefficient was determined to be (1.6 ± 0.2) × 10−18 molecule−1 cm3 s−1.
• The termolecular rate coefficient for XeI excimer production is (2 ± 1) × 10−35 molecule−2 cm6 s−1, with a radiative lifetime of approximately 100 ns.

Conclusions:

• Xenon efficiently enhances the magnetic dipole transition of iodine through an exciplex intermediate.
• The quantified rate coefficients provide insights into the collisional dynamics and kinetics of the process.
• Similar collisional enhancement effects were observed with other gases, including C2F6, SF6, Kr, Ar, and i-C3F7I.