Pb. Armentrout et Mt. Rodgers, An absolute sodium cation affinity scale: Threshold collision-induced dissociation experiments and ab initio theory, J PHYS CH A, 104(11), 2000, pp. 2238-2247
Threshold collision-induced dissociation of Na+(L) with xenon is studied us
ing guided ion beam mass spectrometry. The ligand L includes ethene, benzen
e, phenol, ammonia, acetaldehyde, acetone, and N,N-dimethylformamide. In al
l cases, the primary product formed corresponds to endothermic loss of the
neutral ligand and the only other product observed is the result of ligand
exchange processes to form NaXe+. The cross-section thresholds are interpre
ted to yield 0 and 298 K bond energies for Na+-L after accounting for the e
ffects of multiple ion-molecule collisions. internal energy of the reactant
ions, and dissociation lifetimes. Ab initio calculations at several levels
of theory compare favorably to the experimentally determined bond energies
for these and previously studied systems, L = Ar, CO, dimethyl ether, H2O,
methylamine, imidazole, dimethoxyethane, and several alcohols. Combined, t
hese ligands cover a very wide range in binding energies, and thereby help
to establish an absolute scale for sodium cation affinities.