Quantum threshold energy

Exact quantum threshold energies for 0( P) + H2(v) OH(v ) 4- H using various potential energy surfaces... 

Passing through the threshold energy for ionization of liquid alkanes, the quantum yield of ionization, [Pg.368]

The introduction of laser technology also permitted the determination of related data, such as the distribution of rotational-vibrational quantum states of the products of the unimolecular dissociation [75, 76]. It was found that in the threshold energy region of a unimolecular dissociation,... 

A relatively simple spectroscopic model of O3 absorption in the middle ultraviolet has been proposed (Adler-Golden et al., 1982). This model assumes that the internal energy of an O3 molecule adds fully to that of the absorbed ultraviolet photon and that the quantum yield of O ( Eh) varies smoothly from zero at some threshold energy (calculated as being 32900 cm ) to unity 600 cm above this threshold. The model, which is quite successful in rationalizing the observed Hartley band spectrum for vibrationally excited O3, accurately reflects the experimental temperature dependence of the ( Dz) yield at 313 nm and also predicts a dependence of oCdj) ) upon wavelength in the region above 304 nm that is quite similar to that observed in a previous experimental study... 

This wavelength corresponds closely to the threshold energy for the process, which is 140 nm. Since the efficiency for production of CS(A n) parallels the Rydberg structure in the CS2 absorption spectrum in the wavelength interval below 133.7 nm and above the ionization limit, it is suggested that the dissociation comes from these states rather than from a repulsive state and proceeds with high quantum efficiency. 

The Franck-Hertz experiment and atomic energy levels Electrons can excite atoms from one quantum state to another by energy transferred during collisions. The threshold energy for excitation exactly matches the emission of light as the atom drops back down to the lower state, thus confirming the existence of quantized states and showing that they may be excited by either mechanical impact of electrons or absorption of photons. 

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