FLUORESCENCE ANALYSIS OF LASER PRODUCED RADICALS AND ATOMS

Article abstract of DOI:10.1016/0022-2860(90)80279-S

The IR-MPD of C2H4 and C2H5Cl leads to C2-radicals in electronic excited states (d³ ? g) and electronic ground state (a³ ? u).Treating the measured fluorescence of the C2-radicals in the visible range as a measure for the radical concentration, we have found that the radical concentration depends quadratically on the laser fluence and with the power of 2 on the parent gas pressure.The addition of buffer gas Xe leads to an enhancement of the radical concentration due to rotational relaxation. --- By UV-photolysis of Mo(CO)6 neutral Mo-atoms are produced (at 308 nm as well as 248 nm). --- The intensity dependences of the fluorescence of the excited Mo-atoms indicate direct 2-photon absorption at 248 nm and 3- or 4-photon absorption at 308 nm.An upper limit of the dissociation energy is estimated to be E_diss = 5.6 eV.