Sodium atoms quenching

The resulting doublet sodium atom can then emit light at the sodium TMiric at 589 nm. With so many steps requiring atomic sodium, its concentration, which increases with temperature, significantly affects the chemiluminescent yield. Therefore, the temperature of the solid sodium must be tightly controlled. The excited sodium halide is readily quenched by ambient air molecules, so the system works best at reduced pressure. 

The results obtained so far with collisional energy-transfer spectroscopy are restricted to excited sodium atoms A = Na(32/,3/2) and quenching by a variety of simple polar and nonpolar molecules. The technique is applicable to any vaporizable molecule and will be available for a number of other atoms as well in due course with the progress of laser technology. The E-V-R transfer processes from and to sodium atoms have a number... 

In addition, it was shown that the higher vibrational levels of CO were excessively populated, due to quenching of Na(3 P) by CO. It is of interest to note that reaction of sodium atoms with nitrous oxide as suggested in the above scheme does not occur when sodium atoms and nitrous oxide are co-condensed at low temperatures (Section 5.4, ref. 304). 

The powerful technique of two-photon absorption, which permits limitations of Doppler broadening to be overcome (see Chapter 1), has been used in a study on sodium atoms in which the Stark effect in the 5s 2Si and 4d D and D levels was observed.188 The radiative lifetimes of the S and D Rydberg levels of Na,189 the use of laser-induced resonance fluorescence for the measurement of small concentrations of Na vapour,170 the quenching of Na(32P) and K(42P) by N2, 02, H2, and HaO,171 the chemi-ionization reactions of photoexcited atoms,172 and excitation of the K(42P ) level in collisions with rare-gas atoms173 have been the subjects of recent reports. 

An optically excited sodium atom Na(3F) with a spontaneous lifetime r(3F) = 16ns is placed in a cell filled with lOmbar nitrogen gas at a temperature of T = 400K. Calculate the effective lifetime Teff (3F) if the quenching cross section for Na(3F)-N2 collisions is = 4 x 10 cm. ... 

Although this energy release would be sufficient to produce Na ( P), quenching experiments show that the energy released in reaction (3) does not pass into the sodium atom, but produces vibrationally excited NaCT,... 

The principal impurity in potassium metal is sodium. Potassium s purity can be accurately deterrnined by a melting point test (Fig. 2) or atomic absorption if necessary after quenching with alcohol and water. Traces of nonmetallic impurities such as oxygen, carbon, and hydrogen can be deterrnined by various chemical and physical methods (7,8). 

The threshold wavelength of incident photons to produce the electronically excited Na(2P) is 2440 A. The quenching cross sections by H2. HC1, C02, and H20 for the sodium D lines have been measured as a function of exciting wavelength above 500"C. The quenching cross sections by HCI and C 02 decrease with an increase of relative velocities between the excited Na atoms and quenching molecules [Hanson (441), Earl et al. (332, 333)]. 

Poisoning studies carried out by several groups have shown that the equivalents of poison needed to quench the catalytic activity of the dealuminated Y-type zeolites are much less than the number of Alf atoms. Beyerlein et al. (9) reported that residual sodium cations extensively decreased the isobutane cracking activity of steam-dealuminated Y-type zeolites. From their results it was concluded that only one-third of the Alf atoms were associated with strong acidity throughout the Si/Al > 5 composition domain. 

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