EELS Electron-energy-loss Incident electrons are Surface energy states ... [Pg.314]

MS Mossbauer Spectroscopy [233-236] Chemical shift of nuclear energy states, usually of iron Chemical state of atoms... [Pg.318]

Vibrational energy states are too well separated to contribute much to the entropy or the energy of small molecules at ordinary temperatures, but for higher temperatures this may not be so, and both internal entropy and energy changes may occur due to changes in vibrational levels on adsoiption. From a somewhat different point of view, it is clear that even in physical adsorption, adsorbate molecules should be polarized on the surface (see Section VI-8), and in chemisorption more drastic perturbations should occur. Thus internal bond energies of adsorbed molecules may be affected. [Pg.584]

It is now necessary to examine the partition function in more detail. The energy states for translation are assumed to be given by the quantum-mechanical picture of a particle in a box. For a one-dimensional box of length a. [Pg.607]

To illustrate the use of the variational prineiple, results are presented here for ealeulations of the five lowest energy states (the ground state and the first four exeited states) of a partiele subjeet to the potential... [Pg.41]

The Kronig-Peimey solution illustrates that, for periodic systems, gaps ean exist between bands of energy states. As for the ease of a free eleetron gas, eaeh band ean hold 2N eleetrons where N is the number of wells present. In one dimension, tliis implies that if a well eontains an odd number, one will have partially occupied bands. If one has an even number of eleetrons per well, one will have fully occupied energy bands. This distinetion between odd and even numbers of eleetrons per eell is of fiindamental importanee. The Kronig-Penney model implies that erystals with an odd number of eleetrons per unit eell are always metallie whereas an even number of eleetrons per unit eell implies an... [Pg.105]

The orthogonality condition assures one that the lowest energy state will not converge to core-like states, but valence states. The wavefimction for the solid can be written as... [Pg.113]

very large) or T is zero, tire system is in the lowest possible and a non-degenerate energy state and U = -N xH. If eitiier // or (3 is zero, then U= 0, corresponding to an equal number of spins up and down. There is a synnnetry between the positive and negative values of Pp//, but negative p values do not correspond to thennodynamic equilibrium states. The heat capacity is... [Pg.403]

In die potential section shown on the right hand side of figure A3,13,4 the subset of A energy states is... [Pg.1065]

Figure Bl.11.8. Combmed energy states for two spurs I and S (e.g. FI and C) with an exaggerated representation of how their mutual aligmnent via eoupling affeets their eombined energy. |

To see how it might make sense that a property sueh as the kinetie energy, whose operator (- j /2nig)V involves derivatives, ean be related to the eleetron density, eonsider a simple system ofN non-mteraeting eleetrons moving in a tliree-diniensional eubie box potential. The energy states of sueh eleetrons are known to be... [Pg.2180]

Methods that are based on making the fiinctional (T // T ) / ( T T ) stationary yield upper bounds to the lowest energy state having the synnnetry of the CSFs in T. The Cl and MCSCF methods are of this type. [Pg.2186]

QMC teclmiques provide highly accurate calculations of many-electron systems. In variational QMC (VMC) [112, 113 and 114], the total energy of the many-electron system is calculated as the expectation value of the Hamiltonian. Parameters in a trial wavefiinction are optimized so as to find the lowest-energy state (modem... [Pg.2220]

In a defect-free, undoped, semiconductor, tliere are no energy states witliin tire gap. At 7"= 0 K, all of tire VB states are occupied by electrons and all of the CB states are empty, resulting in zero conductivity. The tliennal excitation of electrons across tire gap becomes possible at T > 0 and a net electron concentration in tire CB is established. The electrons excited into tire CB leave empty states in tire VB. These holes behave like positively charged electrons. Botli tire electrons in the CB and holes in tire VB participate in tire electrical conductivity. [Pg.2881]

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