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Disconnected excitations

If the field excitation is also lost, the generator will run as an induction motor again driving the primer mover as above. As an induction motor, it will now operate at less than the synchronous speed and cause slip frequency current and slip losses in the rotor circuit, which may overheat the rotor and damage it, see also Section. 1.3 and equation (1.9). A reverse power relay under such a condition will disconnect the generator from the mains and protect the machine. [Pg.511]

The valence correlation component of TAE is the only one that can rival the SCF component in importance. As is well known by now (and is a logical consequence of the structure of the exact nonrelativistic Bom-Oppenheimer Hamiltonian on one hand, and the use of a Hartree-Fock reference wavefunction on the other hand), molecular correlation energies tend to be dominated by double excitations and disconnected products thereof. Single excitation energies become important only in systems with appreciable nondynamical correlation. Nonetheless, since the number of single-excitation amplitudes is so small compared to the double-excitation amplitudes, there is no point in treating them separately. [Pg.38]

Furthermore, ec-CCSD only considers triple and quadruple excitations appearing in the Cl wavefunction (i.e., those 3- and 4-body excitations included in Sm) and they are treated non-iteratively. (SC) CAS-SDCl uses the same subset of triples and quadruples in an iterative process, and, additionally, an approximation to the disconnected components of the external triple and quadruple excitations (i.e., those belonging to S ). These terms are labelled as ext in eqs. (20) and (21). This is, indeed, an approximation, because the exact disconnected C]C2 and terms should be written as ... [Pg.78]

Finally, (SC) CAS-SDCl involves, iteratively, excitations Cf i >4 and also approximations to high order disconnected external terms. [Pg.78]

Obviously, we gain precisely the same expressions as in the multi-root theory since we postulated the same form of the effective Hamiltonian. We recall that all matrix elements of the effective Hamiltonian are expressed by means of connected diagrams only in the case of diagonal elements just connected vacuum diagrams may come into consideration and in the case of off-diagonal elements at least one part of a disconnected diagram would correspond to an internal excitation. [Pg.85]

Let us consider a solid that contains only one type of electron trap of volume density N at the discrete level ( and a set of occupied deeper electron traps of density M. The experiment is performed in a temperature range in which traps N empty but traps M remain thermally disconnected and act only as an untapped reservoir of trapped electrons. The density of recombination centers is unspecified, but a density/of them is empty. AtT = Tq, a concentration of /o empty recombination centers exists due to excitation. At these conditions, charge neutrality of the sample is of the form... [Pg.12]

Diagrams 93 and 94 vanish because the disconnected parts that represent H (the open rectangular vertexes) are zero because of Eq. (2-75). The H disconnected part in 95, however, does not vanish in CCSD. The double circle vertex represents R (the contribution of the reference determinant in the excited-state wave function), which is also nonzero if the excited-state symmetry is the same as that of the reference state. This means that unlinked contributions do exist in Eq. (2-94) and they arise from 95 as, e.g.,... [Pg.57]


See other pages where Disconnected excitations is mentioned: [Pg.4]    [Pg.76]    [Pg.618]    [Pg.1712]    [Pg.148]    [Pg.4]    [Pg.76]    [Pg.618]    [Pg.1712]    [Pg.148]    [Pg.153]    [Pg.732]    [Pg.762]    [Pg.133]    [Pg.137]    [Pg.282]    [Pg.156]    [Pg.156]    [Pg.161]    [Pg.168]    [Pg.141]    [Pg.7]    [Pg.78]    [Pg.90]    [Pg.91]    [Pg.92]    [Pg.78]    [Pg.90]    [Pg.91]    [Pg.92]    [Pg.94]    [Pg.102]    [Pg.674]    [Pg.225]    [Pg.212]    [Pg.1299]    [Pg.337]    [Pg.337]    [Pg.34]    [Pg.161]    [Pg.73]    [Pg.27]    [Pg.54]    [Pg.32]    [Pg.359]   
See also in sourсe #XX -- [ Pg.75 ]




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