Study of Energy-Transfer Processes in Electronic Ground States

3 Study of Energy-Transfer Processes in Electronic Ground States 

Most infrared molecular lasers, such as the CO2 laser, the HCl laser, and many other chemical lasers, are based on colli sional energy transfer between vibrational-rotational levels of the laser molecule and other atoms or molecules. Such lasers may therefore be called energy-transfer lasers [12.17]. Also in the visible region many molecular cw laser systems, where the laser transition terminates on rotation-vibration levels of the electronic ground state, rely on efficient collisional energy transfer between these levels and neighboring vibration-rotation levels in order to achieve a sufficiently fast 

The internal energy + E of a molecule M may be transferred during a collision with another molecule AB into vibrational energy of AB (V- V transfer), rotational energy (V- R transfer), electronic energy (V- E transfer), or translational energy of the collision partners (V- T transfer). In  

A famous example of a nearly resonant V- V energy transfer process is the collision-induced energy transfer from vibrationally excited N2 molecules onto CO2 molecules 

This is the major excitation process for populating the upper laser level in the CO2 laser (Fig.12.10). 

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