Geometry of the CheESE model showing the direction of the applied potential, ±V. We use a cuboid box, with the xy-plates representing the electrodes of a nano-device. The coordinate origin is equidistant from the two plates.
Stabilization of the benzene (blue lines), benzene anion (red lines), and glycine (green lines) molecules due to CheESE image charges in the case Φfixed(s) = 0 with varying Δz. Part (a) compares the total energies, , shown as dotted lines, with the reference free-space energies, shown as solid lines, for an xy-plate area of 200×200 bohr2. Parts (b)–(d) highlight the CheESE effect as the difference between and the free-space energy for (b) benzene, (c) glycine, and (d) benzene anion, with two choices of plate area.
Energies of neutral benzene (blue lines), benzene anion (red lines), and glycine (green lines), with an applied potential, V, as given in Eq. (39), an xy-plate area of 108×108 bohr2, and Δz = 54 bohr. The total CheESE energies, , are shown as dashed lines, and the reference free-space energies are shown as solid lines.
Energy changes for different applied potentials when including image charge effects in addition to a static field. E image, as given by Eq. (25), is shown for (a) neutral benzene, (b) glycine, and (c) benzene anion, using an xy-plate area of 108×108 bohr2, and Δz = 54 bohr.
Energy profiles of the lowest lying molecular orbitals of (a) neutral benzene, (b) glycine, and (c) benzene anion, with an applied potential, V, an xy-plate area of 108×108 bohr2, and Δz = 54 bohr. Since there are no relevant orbital crossings, only the HOMO and LUMO are shown for the anion and glycine.
Static field and image charge contributions (see main text for definitions) to the HOMO–LUMO gap for neutral benzene (blue line), glycine (green line), and benzene anion (red line) with varying applied potential, V, an xy-plate area of 108×108 bohr2, and Δz = 54 bohr.
Structure of CheESE implementation.
Energy differences in kcal/mol, according to Eqs. (24) and (25), giving the change, E static, to the total energy on applying a static field with potential V/a.u., and the additional CheESE image charge contribution, E image.
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