Reaction Kinetics of Sc, V, Cr, Co and Ni With N2O
Abstract
The purpose of this experiment was to determine the gas phase reactivities of N2O with the following first-row transition metal atoms: Sc(a2D3/2), V(a4F3/2), Cr(a7S3), Co(a4F9/2) and Ni(a3D3, a3F4). Reactions were studied in the temperature range of 298K-623K. Sc, V, Cr, Co and Ni atoms were produced by photodissociation of Sc(hfa)3, Sc(TMHD)3, V(CO)6, V(CO)4(C5H5), V(C5H5)2, Cr(CO)6, Co(C5H5)(CO)2 and Ni(C5H5)2 respectively. Pseudo first-order conditions were maintained (Transition Metal<<N2O), and atoms were detected using a laser-induced florescence technique. Reactions of the ground states with N2O were temperature dependent. Reactions of Sc, V, Cr and Co with N20 were found to be pressure independent, indicating a bimolecular abstraction mechanism. Removal rate constants for the excited a6DJ and a5S2 states of Cr were found to be fast compared to reactions with the ground state. The rate constants for Sc, V, Cr and Co can be described in Arrhenius form (k=Aexp(-Ea/RT)) by k=1.6x10-10exp(-11.7 kJ/mol/RT) cm3s-1, k=4.6xl0-11 exp(-10.7 kJ/mol/RT) cm3s-1, k=4.2x10-11 exp(-20.4 kJ/mol/RT) cm3s-1, and k=2.Ox1O-10exp (kJ/mol/RT) cm3s-1, respectively. The rate constants for Ni were found to be pressure dependent at low temperatures suggesting a termolecular reaction.
Document Details
- Document Type
- Technical Report
- Publication Date
- May 07, 1997
- Accession Number
- ADA418485
Entities
People
- Erica J. Kolsch
Organizations
- United States Naval Academy