Photoassociation Spectroscopy of Colliding Atoms

Second the photoassociation spectroscopy of cold atoms allows the detailed investigation of the long-range part of the difference potential between 

the spectroscopy of cold collisions may open the way to a new chemistry at ultralow temperatures, which allows more detailed insights into the mechanisms of molecular reactions and their dependence on the relative kinetic energy of the reactants [13.139]. 

A historical overview on the development of our understanding of the dynamics of molecular processes during the last 50 years can be found in [13.140]. 

1 Assume an inelastic cross section of = 10 cm for collisions between excited atoms A and partners B, and a velocity-changing cross section ay(Av) = (jQ e p(—Av / v )) for velocity changes Av of atom A. Discuss for ao = 10 cm the line profile of the Lamb dip in the transition A - A if the radiative lifetime is Trad = s, the pressure of partners B is 1 mbar, the 

2 The effective lifetime of an excited molecular level is = 5 mbar) = 8 X 10 s and Zeffip = 1 mbar) = 12 x 10 s for molecules with the mass M = 43 AMU in a gas cell with argon buffer gas at T = 500 K. Calculate the radiative lifetime, the collision-quenching cross section, and the homogeneous linewidth Av(p). 

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