Energy electronic interaction

RESULTS FOR LOW-ENERGY ELECTRON INTERACTIONS WITH DNA AND OTHER BIOMOLECULES... 

Figure 19-3. Unimolecular fragmentation pathways that follow low-energy electron interaction with a diatomic molecule AB. The asterisk in parentheses indicates that the species could be electronically excited. (Reprinted with permission from [21]. Copyright 2000 American Chemical Society.)...

Tung, C. J., Chao, T. C., Hsieh, H. W., and Chan, W. T. 2007. Low-energy electron interactions with liquid water and energy depositions in nanometric volumes. Nucl. Instrum. Methods Phys. Res. B 262(2) 231-239. 

Sanche, L. (2010). Low-energy electron interaction with DNA Bond dissociation and formation of transient anions, radicals, and radical anions. In M. Greenberg (Ed.), Radical and radical ion reactivity in nucleic acid chemistry (p. 239).Hoboken Wiley, ISBN 978-0-470-25558-2. 

L. Sanche, in Radical and Radical Ion Reactivity in Nucleic Acid Ghemistry, M. M. Greenberg (Ed.), Wiley, 2010, pp. 239-293, Low Energy Electron Interaction with DNA Bond Dissociation and Formation of Transient Anions, Radicals, and Radical Anions. 

Electrons interact with solid surfaces by elastic and inelastic scattering, and these interactions are employed in electron spectroscopy. For example, electrons that elastically scatter will diffract from a single-crystal lattice. The diffraction pattern can be used as a means of stnictural detenuination, as in FEED. Electrons scatter inelastically by inducing electronic and vibrational excitations in the surface region. These losses fonu the basis of electron energy loss spectroscopy (EELS). An incident electron can also knock out an iimer-shell, or core, electron from an atom in the solid that will, in turn, initiate an Auger process. Electrons can also be used to induce stimulated desorption, as described in section Al.7.5.6. 

Another mode of electron diffraction, low energy electron diffraction or FEED [13], uses incident beams of electrons with energies below about 100 eV, with corresponding wavelengths of the order of 1 A. Because of the very strong interactions between the incident electrons and tlie atoms in tlie crystal, there is very little penetration of the electron waves into the crystal, so that the diffraction pattern is detemiined entirely by the... 

This gives the total energy, which is also the kinetic energy in this case because the potential energy is zero within the box , m tenns of the electron density p x,y,z) = (NIL ). It therefore may be plausible to express kinetic energies in tenns of electron densities p(r), but it is by no means clear how to do so for real atoms and molecules with electron-nuclear and electron-electron interactions operative. 

Here, t is the nuclear kinetic energy operator, and so all terms describing the electronic kinetic energy, electron-electron and electron-nuclear interactions, as well as the nuclear-nuclear interaction potential function, are collected together. This sum of terms is often called the clamped nuclei Hamiltonian as it describes the electrons moving around the nuclei at a particular configrrration R. 

If vve now expand the expression for the energy as for the ground state, terms analogous to the electron-nucleus and electron-electron interactions can again be obtained. However, the cross-terms are no longer equal to zero as was the case for the ground state, because the... 

The resultant corrections to the SCF picture are therefore quite large when measured in kcal/mole. For example, the differences AE between the true (state-of-the-art quantum chemical calculation) energies of interaction among the four electrons in Be and the SCF mean-field estimates of these interactions are given in the table shown below in eV (recall that 1 eV = 23.06 kcal/mole). 

---