Transcript Wilkinson's catalyst.ppt

High Resolution Laser
Spectroscopy of
Rhodium Monophosphide
A.G. Adam *, M.E. Slaney *, L.E. Downie *, R. Li ‡, W.J. Balfour ‡
Centre for Laser, Atomic, and Molecular Sciences, University of New Brunswick, Fredericton, NB,
E3B 6E2
*Dept. of Chemistry, University of New Brunswick, Fredericton, NB, E3B 6E2
‡Dept. of Chemistry, University of Victoria, Victoria, BC, V8W 3V6
Wilkinson’s Catalyst
Rhodium
Monophosphide
Previous Work
• Medium resolution study by Balfour et al.
[J. Phys. Chem. A 108,8145-46 (2004)]
–
–
–
–
Partial rotational resolution
Dispersed fluorescence
Lifetimes
Ground state electronic configuration of …σ2π4δ4σ2
• Recent theoretical study of triple-bond covalent radii
by Pykkö et al.
[Chem. Eur. J., 11, 3511-20 (2005)]
– Prediction of RhP bond length: r = 1.982Å
Pulsed Laser Survey Scan
Dispersed Fluorescence Analysis
Deslandres Tables (from excitation spectra)
*
*
*
*
*
*
*
*
*
•Variation in vibrational spacing.
•Ground State vibrational progression (507, 502, 498, 492, 488cm-1) gives:
ωe= 500.33 cm-1, ωexe = 2.07.
•Low lying electronic states at 2454 and 4691cm-1.
Pulsed Laser Survey Scan
P Branch = Red
High Resolution Analysis
R Branch = Green
Perturbations
High resolution spectrum of the [22.8]1Σ+–X1Σ+(1,0)
transition with perturbations at P(18) and R(16).
Perturbations
High resolution spectrum of the [22.8]1Σ+–X1Σ+(0,0)
transition with perturbations at P(15) and R(13).
Reduced Term Value Plot
Rotational Constants
Equilibrium Molecular Constants
Conclusions
•
•
•
•
Spectra have been observed and acquired in high
resolution for four families of bands at 19628,
21672, 23183, and 23742 cm-1 above the ground
state. All states are of 1Σ+ symmetry.
Dispersed fluorescence of all bands allowed for a
determination of ground state vibrational constants.
Molecular constants for the ground state and four
excited states have been determined from a global
least squares fit.
W. Balfour has analyzed 17 other bands (some
v"=0, some v"=1) using the high resolution ground
state molecular constants.
Thanks for sticking around for a
small molecule talk in a big
molecule session.
Time for a Beer!