Photodissociation spectroscopy and dynamics of Si-4

The photodissociation of Si-4 has been investigated using fast beam photofr agment translational spectroscopy. The photofragment yield (PFY) spectrum s hows features between 21370 and 22220 cm(-1) corresponding to the 1B(1u) -- > (X) over tilde (1)A(g) transition that are attributed to multi-photon dis sociation. Single-photon dissociation was examined at higher excitation ene rgies ranging from 5.17 to 6.42 eV. The dominant product channel was found to be Si-3 + Si. Experimental photofragment translational energy distributi ons were modeled by phase space theory (PST), indicating statistical photo dissociation with no exit barrier along the dissociation coordinate. PST mo deling yields a dissociation energy of 4.60 +/- 0.15 eV and DeltaH(f,0)(0) (Si-4) = 6.75 +/- 0.24 eV. (C) 2001 Published by Elsevier Science B.V.