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Operator, wave Subject

Besides the inherent lateral natural frequency characteristic, compressors are also influenced by torsional natural frequencies. All torsionally flexible drive trains are subject to non-steady or oscillatory excitation torques during normal operation of the system. These excitation torques can be an inherent function of either the driver or the driven equipment and, when superimposed on the normal operating torque, may appear to be of negligible concern. However, when combined with the high inertia loads of many turbomachinery trains and a torsional resonant frequency of the system, these diminutive ripples can result in a tidal wave of problems. [Pg.390]

The calculation of the Td matrix, involving second derivatives of the electronie wave-functions, is more expensive and subject to numerical inaccuracy than that of Gd-A simple approximation for the third term in eq.(19) is based on a partial expansion of the identity operator in terms of the diabatic basis ... [Pg.364]

Consider the product

point group C2v, written as >1 ( 2) and that (p2 has symmetry B2, i.e. 4>2 B2). It is required to find the symmetry of tp =

wave function tp is subjected to all operations of C2v, starting with C2, noting from the character table that under this operation... [Pg.298]

The calculation of the properties of a solid via quantum mechanics essentially involves solving the Schrodinger equation for the collection of atoms that makes up the material. The Schrodinger equation operates upon electron wave functions, and so in quantum mechanical theories it is the electron that is the subject of the calculations. Unfortunately, it is not possible to solve this equation exactly for real solids, and various approximations have to be employed. Moreover, the calculations are very demanding, and so quantum evaluations in the past have been restricted to systems with rather few atoms, so as to limit the extent of the approximations made and the computation time. As computers increase in capacity, these limitations are becoming superseded. [Pg.76]

It is certainly more constant than that of sediments being introduced into the basin. This fact is due to the greater mobility of material in solution which tends to even out local fluctuations in concentration through the action of waves and currents. The sediment is much less subjected to such a mechanical homogenization process and tends, therefore, to attain equilibrium by localized mineral reaction. The type of thermodynamic system operative is most likely to be "open", where each point of sediment has some chemical variables fixed by their concentration in the sediment (inert components due to their low solubility in the solution) and other chemical components, which are soluble, have their concentration in the sediment a function of their activity in the aqueous solution. The bulk composition of the resulting sediment will be largely determined by the composition of the waters in which it is sedimented and the length of time it has reacted with this environment. The composition of the aqueous solution is, of course, determined to a minor extent by these reactions. [Pg.19]

Hartree-Fock theory makes the fundamental approximation that each electron moves in the static electric field created by all of die other electrons, and then proceeds to optimize orbitals for all of the electrons in a self-consistent fashion subject to a variational constraint. The resulting wave function, when operated upon by the Hamiltonian, delivers as its expectation value the lowest possible energy for a single-detenninantal wave function formed from the chosen basis set. [Pg.203]

All results are based upon master eq. (16). One of the chief deficiencies of many discussions of chemical transitions of excited molecules is made apparent by the formalism. Considerable effort has been devoted to development of electronic wave functions for A and B. Transition probabilities are then discussed in terms of superficial examination of the relationships between the wave functions. In discussions of the subject, considerable bickering may arise because of divergence of opinion as to the goodness of electronic wave functions. While discussion of the quality of approximate wave functions has real significance in structural chemistry, it seems to be a matter of secondary importance in treatment of the dynamic problem at the present time. Almost any kind of electronic wave function is likely to be of better quality than any available perturbation operators (// ). A secondary problem arises from the fact that the vibrational part of ifi1, is likely to be relatively unknown.)- At the present time our best approach to the problem appears to be use of experiments to read back the nature of the perturbation. This leads to an iterative procedure in which the implications of relationships between wave functions are examined experimentally to lead to tentative generalizations that are, in turn, used to predict results of more experiments. The procedure is essentially that used by Zimmerman and his group,7 by Woodward and Hoffman,25 and, in one form or another, by various other authors. [Pg.382]

Before considering particular test methods, it is useful to survey the principles and terms used in dynamic testing. There are basically two classes of dynamic motion, free vibration in which the test piece is set into oscillation and the amplitude allowed to decay due to damping in the system, and forced vibration in which the oscillation is maintained by external means. These are illustrated in Figure 9.1 together with a subdivision of forced vibration in which the test piece is subjected to a series of half-cycles. The two classes could be sub-divided in a number of ways, for example forced vibration machines may operate at resonance or away from resonance. Wave propagation (e.g. ultrasonics) is a form of forced vibration method and rebound resilience is a simple unforced method consisting of one half-cycle. The most common type of free vibration apparatus is the torsion pendulum. [Pg.173]

The theory of the multi-vibrational electron transitions based on the adiabatic representation for the wave functions of the initial and final states is the subject of this chapter. Then, the matrix element for radiationless multi-vibrational electron transition is the product of the electron matrix element and the nuclear element. The presented theory is devoted to the calculation of the nuclear component of the transition probability. The different calculation methods developed in the pioneer works of S.I. Pekar, Huang Kun and A. Rhys, M. Lax, R. Kubo and Y. Toyozawa will be described including the operator method, the method of the moments, and density matrix method. In the description of the high-temperature limit of the general formula for the rate constant, specifically Marcus s formula, the concept of reorganization energy is introduced. The application of the theory to electron transfer reactions in polar media is described. Finally, the adiabatic transitions are discussed. [Pg.10]

Due to the fact that the SLG wave function belongs to the GF approximation (Section 1.7), it is subject to numerous selection rules characteristic of GF. Their explicit form can be easily obtained using the second quantization formalism. Since the operators of electron creation on the right and left HOs satisfy usual anticommutation relations for orthogonal basis and the number of particle operators have the usual form ... [Pg.138]


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See also in sourсe #XX -- [ Pg.1083 ]




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