Multiphoton mass spectrometery

Multiphoton absorption can be produced with high efficiency if the laser light is converted to ultraviolet by a nonlinear crystal and then softly focused into a molecular gas. The excitation energy is sharp at several discrete energies because of the absorption of many monochromatic photons. Eventually fragmentation outruns further absorption and thresholds for bond-breaking processes can be determined accurately. As the laser intensity is increased, successively stronger bonds are ruptured, thus allowing successive decomposition steps in a large polyatomic molecule, a method of possible application in structure studies