ABSTRACT
In view of new metal catalysis reactions, CuF-chemiluminescent and plasma reactions in a gaseous Cu-CF(4) system are studied as well as their interactions with a magnetic field. As for the chemiluminescent reaction, the spectroscopic analysis of the CuF chemiluminescence in the reaction of CF(4) with Cu emitted by laser ablation with a fundamental beam of a Nd(3+):YAG laser indicates that the rotational, vibrational, and translational temperatures of the product CuF are rather similar, suggesting the simple heating mechanism. In this mechanism, the high translational energy of the reactant Cu atom will be used to go over the early barrier. The mechanism is evidenced by experimentally observing that the reaction barrier decreases with an increase in the translational energy of the reactant Cu by an increase in the laser power for ablation. On the other hand, in the further study, we find that Cu emitted by laser ablation can switch the plasma in an electric field less than that necessary for the direct discharge in dc-plasma and call it PLASLA (plasma switching by laser ablation). In PLASLA, the plasma is formed by the first ablation, quenched by the second ablation, formed by the third ablation, quenched by the fourth ablation, and so on. Thus PLASLA will be a promising new metal catalysis process for materials science. In particular, the cooperation of the ablation laser with the laser for photoreactions will be significant as a new technique. The studies on the mechanism of PLASLA with metals of Cu, Al, Ag, Zn, Co, Ni, Ti, Mo, and W indicate that the metals are classified into three groups. It is of great interest that the classification agrees with the classification by their electronic configurations. PLASLA is found to be formed rather easily and stable with Al, Ag, Cu, and Zn of group I. Species such as C, C(+), C(2+), and C(2) are observed in the time-resolved spectra of PLASLA luminescence at 0.5 mus after laser ablation, suggesting carbon polymers as the final product. In fact, the TOF (time-of-flight) mass spectrometric analysis of the product material confirms it. Furthermore, PLASLA and the CuF-chemiluminescent reaction are studied in a magnetic field. In the chemiluminescent reaction, we propose that the field switches the reaction paths by mixing the singlet and triplet potential surfaces at level crossing by breaking the spin selection rule. The field affects PLASLA through the MHD (magneto-hydrodynamic) processes such as E x B drifts and cyclotron circulation, as well as the singlet-triplet mixing.
