Electronic Supplementary Material
Polarization at Metal-Biomolecular Interfaces in Solution
Hendrik Heinz, Kshitij C. Jha, Jutta Luettmer-Strathmann, Barry L. Farmer, and Rajesh
R. Naik
Polarization Energy per Surface Area Using the Approximate Formula Equation (6)
Polarization energies per surface area according to the approximate equation (6)
are shown in figure S1. The values are of similar magnitude as those according to the
exact solution equation (4) (figure 4), although less polarization is seen for a solution of
peptide A3 in comparison to water. As a consequence of the modified integral, equation
(6) provides a lower bound of the exact values near and above the jellium edge. The
implementation of the Ewald summation (Materials Studio 4.0 Program Suite) imposes a
zero dipole moment on the simulation box which eliminates tail contributions to the
polarization energy (see figure 4). Therefore, polarization energies in figure S1 are
effectively decreased at positions of the image plane z im above the jellium edge (toward
the solution), similar near the jellium edge, and increased at positions of the image plane
<-1 Å below the jellium edge (toward the metal). Each data point reflects an average over
15 snapshots throughout the trajectory.
1 of 3
2
Polarization energy per surface area (mJ/m )
A
Interface
Edge
0
A3 (neutral peptide)
Flg-Na3 (charged peptide)
Water
Au {111} surface
-50
-100
-200
Jellium Edge
-150
0
-10
-20
-30
-40
-50
-60
-4
-3
-2
-1
0
-250
-16
-2.5
-2.0
-1.5
-1.0
-0.5
0.0
0.5
Position of image plane (Å)
2
Polarization energy per surface area (mJ/m )
B
Interface
Edge
0
A3 (neutral peptide)
Flg-Na3 (charged peptide)
Water
Au {100} surface
-50
-100
0
-10
Jellium Edge
-150
-20
-30
-200
-40
-50
-4
-3
-2
-1
0
-250
-16
-2.5
-2.0
-1.5
-1.0
-0.5
Position of image plane (Å)
2 of 3
0.0
0.5
Figure S1. Polarization energy per surface area as a function of the position of the image
plane (A) on the Au {111} surface and (B) on the Au {100} surface in contact with water
and peptide solutions using the approximate method described by equation (6). The
position of the image plane is near the jellium edge.
3 of 3