Spectral Signatures of Proton Vibrations in
Water Clusters
Jeffrey M. Headrick
JOHNSON LAB
Yale University
The Real Hero’s
Why the Fascination?
ACID
Substance
H+
H+H+H+ +
+H
+
+
H
H H
+
H
+
H
H+ + H+ H+
H H+
1903
Svante Arrhenius
“…electrolytic theory
of dissociation.”
Past Players…
•Bulk Investigations Utilizing Spectral Subtraction
M. Falk and P. A. Giguere, Can. J. Chem., 35, 1195 (1957).
N. B. Librovich, V. P. Sakun, N. D. Sokolov, Chem. Phys., 39, 351 (1979).
J. Kim, U. W. Schmitt, J. A. Gruetzmacher, G. A. Voth, N. E. Scherer,
J. Chem. Phys., 115, 737 (2002).
J. Kim, U. W. Schmitt, J. A. Gruetzmacher, G. A. Voth,
N. E. Scherer, J. Chem. Phys., 115, 737 (2002).
Past Players…
•Hydronium Ion and the Eigen Cation
M. H. Begemann, C. S. Gudeman, J. Pfaff, and R. J. Saykally
Phys. Rev. Lett. 51, 554 (1983).
L. I. Yeh, M. Okumura, J. D. Meyers, J. M. Price, Y. T. Lee
J. Chem. Phys. 91, 7319 (1989).
Hydronium
Cation
Eigen
Cation
M. Eigen and L. D. Maeyer, Proceedings of the Royal Society of London, 247, 505 (1958)
Past Players…
•Zundel Ion
L. I. Yeh, M. Okumura, J. D. Meyers, J. M. Price, Y. T. Lee
J. Chem. Phys. 91, 7319 (1989).
+
H3O Signal
K. R. Asmis et. al., Science 299,
1375 (2003).
Zundel
Cation
0
800
1000
1200
1400
1600
-1
Photon Energy (cm )
P. Schuster, G. Zundel, C. Sandorfy, Eds., (North – Holland, Amsterdam, 1976).
1800
The Machine
Wiley and McLaren, Rev. Sci. Instum., 26, 1150, 1955
The Machine
Ionization Region
Wiley and McLaren, Rev. Sci. Instum., 26, 1150, 1955
The Machine
Ionization Region
The Machine
Nd: YAG
Time of Flight
The Machine
600 – 1980 cm-1
Nd: YAG
Detection Region
30
35
40
TOF (s)
45
50
The Eigen Cation
H3O+
bend
na
nb
ns
H3O+
asym
1000
1400
1800
2200
2600
3000
Photon Energy (cm-1)
3400
3800
What if we Mimic a Solvent Fluctuation
Figure 3
1000
1400
1800
2200
2600
3000
Photon Energy (cm-1)
3400
3800
Pushing
theMimic
Solventa Fluctuation
Further
What if we
Solvent Fluctuation
Figure 3
1000
1400
1800
2200
2600
3000
Photon Energy (cm-1)
3400
3800
Going Towards the Bulk
n
2
3
4
5
6
7
8
?
9
10
11
1000
1400
1800
2200
2600
3000
Photon Energy (cm-1)
3400
3800
Final Thoughts
n
2
3
4
5
6
7
8
9
10
11
1000
1400
1800
2200
2600
3000
Photon Energy (cm-1)
3400
3800
•Minor changes in the
hydration structure yield
dramatic shifts in the spectral
feature nominally associated
with the excess charge.
Why the Fascination?
ACID
Substance
H
Johannes Bronsted
Thomas Lowry
RH + H2O ↔ H3O+ + R
Acid1
Base1
Acid2
Base2