화학공학소재연구정보센터
Journal of Physical Chemistry, Vol.98, No.50, 13286-13293, 1994
Kinetics of Ti(A(3)F, A(5)F) and V(A(4)F, A(6)D) Depletion by NH3 and H2S
The kinetics of depletion of ground-state Ti(a(3)F) and V(a(4)F) and excited-state Ti(a(5)F) and V(a(6)D) upon interactions with NH3 and H2S are studied in a fast-flow reactor at a He pressure of 0.70 Torr. No depletion of ground-state Ti(a(3)F) and V(a(4)F) was observed upon interaction with NH3. Depletion of Ti(a(3)F) and V(a(4)F) by H2S did occur but inefficiently, with measured effective 300 K bimolecular rate constants of (0.44 +/- 0.12) x 10(-12) and (4.0 +/- 0.2) x 10(-12) cm(3) s(-1), respectively. In contrast to the ground-state metals, depletion of excited-state metal atoms Ti(a(5)F) and V(a(6)D) by NH3 and H2S occurred efficiently. The measured effective rare constants for depletion of Ti(a(5)F) by NH3 and H2S are (39 +/- 11) x 10(-12) acid (142 +/- 13) x 10(-12) cm(3) s(-1), respectively. The measured rate constants for depletion of V(a(6)D) with these respective gases an (95 +/- 8) x 10(-12) and (69 +/- 5) x 10(-12) cm(3) s(-1). The reactive differences between the ground and excited states as well as between metals provide important clues about N-H and S-H bond activation in these systems.