Effect degeneration

Endocrine Effects. Degeneration of the adrenals was noted in female mice exposed to 1.1 mg/kg/day or more hydrazine for 25 weeks (Biancifiori 1970). No adverse effects were noted in the thyroid of mice exposed to 9.3 mg/kg/day hydrazine for 25 weeks. Similarly, no effects were observed in the thyroid or adrenals of hamsters exposed to 5.3 mg/kg/day hydrazine for 15-20 weeks (Biancifiori 1970). 

As discussed in Section III.B, quantum interference structure tends to be quenched by these sums, and if the transition is classically allowed, the semi-classical theory then effectively degenerates to a completely classical result. 

Perpete, Quinet and Champagne have shown that vibrational contributions to the y-hyperpolarizability of various symbioticaUy substituted quadrupolar JT-conjugated molecules are large. Using ab initio calculations at the HF level they calculate the response functions for the dc-Kerr effect, degenerate four wave mixing, hyper-Raman effect and electric field induced SHG. 

B, E, and G families of Csh (Nobles and Brown, Jr. 2004) may provide a basis for designing more effective degenerate primers. 

This average over molecular orientations is equivalent to an average over initial and a sum over final rotational and vibrational states under the assumption that the vibrational and rotational states are effectively degenerate (so closure relations can be used) for the electronic incident energies involved. To calculate an integral cross section as in the examples below, we integrate the cross section in equation (20) over the polar angles that orient the final momentum, kpy with respect to the initial momentum... 

Jahn-TeHer effect The Jahn-Teller theorem states that, when any degenerate electronic slate contains a number of electrons such that the degenerate orbitals are not completely filled, the geometry of the species will change so as to produce non-degenerate orbitals. Particularly applied to transition metal compounds where the state is Cu(II)... 

The co-ordination number in ionic compounds is determined by the radius ratio - a measure of the necessity to minimize cationic contacts. More subtle effects are the Jahn-Teller effect (distortions due to incomplete occupancy of degenerate orbitals) and metal-metal bonding. 

Baer M, Yahalom A and Engelman R 1998 Time-dependent and time-independent approaches to study effects of degenerate electronic states J. Chem. Phys. 109 6550... 

The stoi7 begins with studies of the molecular Jahn-Teller effect in the late 1950s [1-3]. The Jahn-Teller theorems themselves [4,5] are 20 years older and static Jahn-Teller distortions of elecbonically degenerate species were well known and understood. Geomebic phase is, however, a dynamic phenomenon, associated with nuclear motions in the vicinity of a so-called conical intersection between potential energy surfaces. 

Non-adiabatic coupling is also termed vibronic coupling as the resulting breakdown of the adiabatic picture is due to coupling between the nuclear and electi onic motion. A well-known special case of vibronic coupling is the Jahn-Teller effect [14,164-168], in which a symmetrical molecule in a doubly degenerate electronic state will spontaneously distort so as to break the symmetry and remove the degeneracy. 

If the states are degenerate rather than of different symmetry, the model Hamiltonian becomes the Jahn-Teller model Hamiltonian. For example, in many point groups D and so a doubly degenerate electronic state can interact with a doubly degenerate vibrational mode. In this, the x e Jahn-Teller effect the first-order Hamiltonian is then [65]... 

Figure 29, The effect of the phase-preserving component of the degenerate 2 distorting mode, It may be regarded as a major component of the reaction coordinate that leads to the A] structure (going left, one phase of the mode). Going right, the other phase of the same vibration, the B2 state is formed. (A type-V structure is also obtained along the same coordinate).

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