The use of floor-covering has been shown to substantially alter the behavior of captive terrestrial primates. Experiments with two large family groups of common marmosets (Cullithrix jucchus) and two of cotton-top tamarins (Suguinus oedipus) have shown that the type of floor-covering also beneficially alters the behavior of arboreal monkeys, increasing use of the floor and decreasing inactivity. These effects increased over 2.5 mo, and appeared to be due to the reduced aversiveness of the floor. Hanging screens also produced beneficial effects.

Rate constants have been measured for the reactions of boron atoms with a series of bromomethanes and bromofluoromethanes. The experiments were performed in a linear flow apparatus at 300 K. The bimolecular rate constants were obtained by measuring the density of boron along the flow tube as a function of reactant gas density. The measured rate constants in units of cubic centimeters per molecule per second are for CBr4, 4.2 X 1CT11; for CBr3H, 8.1 X 1CT11; for CBr2H2, 1.3 X 10"10; for CBrH3, 5.7 X 10"11; for CBr3F, 3.8 X 10"11; for CBr2F2, 9.2 X 10"11; for CBrF3, 1.4 X 10"11; for CH3F, <8 X 10"14; and for CBr2Cl2, 1.4 X 10"10. These results are compared to the previously published work on the chlorofluoromethanes where the reactivity of the chlorine site was substantially reduced by fluorine substitution. The corresponding decrease in reactivity of the bromine site is not present in the bromofluoromethanes.

6 'P, 6 "F: 6'P, Y Ha + Br('P1 6150 Hg Br Figure 8. Schematic diagram of the electronic states showing the various channels of HgBrl photofragmentation.which decay via dissociation to electronically excited HgBr molecules and Br atoms:(4) HgBr2 -HgBr2* -HgBr* + BrThe fate of resulting HgBr* photofragments could be either dissociation to Hg(6p3P) and Br atoms or thermalization to HgBr(D211) molecules via electronic crossing, as presented in Figure 8, and given by the processesThe addition of nitrogen buffer gas up to 7 mbar gives an increase in the HgBr(D-X) fluorescence ( Figure 3) since collisional deactivation favors the above processes. A further increase in the nitrogen gas pressure promotes radiationless electronic-transfer processes, which deactivate HgBr molecules from the D state to the lower lying B state ( Figure 8). This deactivation is more pronounced for the low vibrational levels (u' = 0-7), while the high v' levels undergo earlier vibrational deactivation.Furthermore, the formation of highly excited Hg(8d3D) atoms takes place with the absorption of an additional KrF photon by metastable Hg(6p3P) atoms: 2hv HgBr* -Hg(63P) + Brwhich are produced by the dissociation process, (5a). This is indicated by the 2.6 power dependence of the observed Hg-(8d3Dl-+6p3Po) fluorescence on the laser intensity ( Figure 5) and by the drastic decrease in the above fluorescence with the addition of a buffer gas in the pressure range 7-1000 mbar ( Figure 6). It was also proven experimentally that excited Hg(8d3D) atoms could not be produced by a two-photon (KrF laser) excitation of ground-state Hg(61So) atoms. At low nitrogen gas pressures up to 7 mbar, collisional energy transfer assists the formation of metastable Hg(6p3P) atoms, through process 5a and with subsequent excitation increases the Hg(8d3Dl) atoms population and the resulting Hg(8d3D1-6p3Po) fluorescence, as shown in Figure 6. At higher pressures, collisional quenching of excited Hg(6p3P) atoms starts to compete with the up-pumping to the (8d3D1) state and thus results in a drastic decrease in both Hg(8d3Dl+6p3Po) and Hg(6p3Po-61So) transitions ( Figure 6). ConclusionsThe KrF laser photolysis of HgBrz molecules produced two strong fluorescence emissions in the visible and the ultraviolet, which are recognized as the HgBr(B-X) and HgBr(D-X) transitions. The vibrational analysis of the HgBr(D-X) transition was done and showed a high degree of vibrational excitation for the primary HgBr photofragments. The KrF laser-induced excitation produces highly excited HgBr2 molecules with a direct two-photon absorption through a real intermediate l'n, electronic state. Thus, the photofragmentation process of HgBr2 molecules occurs either from the highly excited Rydberg state or from the initially excited intermediate state and respectively leads to either excited Hg(6p3P) atoms and HgBr(D) molecules or ground-state Hg(6'So) atoms. Furthermore, collisional electronic transfer processes deexcite the initially formed HgBr(D) molecules to the lower electronic B state, from w...

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