INDEX effective core potential

The static dipole polarizabilities of alkali dimers have been calculated as a function of the internuclear distance and of the vibrational index for both their electronic ground state and lowest triplet state. The method is based on /-dependent pseudopotentials for atomic core representation, Gaussian basis sets, effective core potentials to account for core polarization, the evaluation of molecular orbitals by the restricted HF method, and then a full valence Cl treatment. For all alkali pairs, the parallel and perpendicular components of the ground state a at equilibrium distance Rg scale as the cube of Re, which can be related to a simple electrostatic model of an ellipsoidal charge distribution. So, for the ground state, the longitudinal polarizability exhibits a maximum at a distance corresponding to 1.3-1.5 times the equilibrium distance. 

The inhibition in brain AChE activity is the crucial facet of the neuroloxic effects of anti-ChEs in rodents and other test species, but such a measurement is obviously impossible to make in human subjects and indirect mcthod.s must be utilized. The inhibition in scrum or plasma ChE activity is often used as a index of potential inhibition in brain AChE activity in humans who may be exposed to anti-ChE. In the rat exposed to DFP. a significant hypothermic response was associated with an inhibition in serum ChE activity of 54% (Gordon and Fogelson, 1993), With other OPs, plasma or scrum ChE activity can plummet to below 25% of normal before there is a significant hypothermic effect. A 5-min exposure to vapors of DFP in the mouse causes core temperature to decrease by mure than 4 C within 30 min and remains depressed for approximately 4 hr (Scimeca et al., 1985). This was associated with a 66% inhibition in brain AChE activity that remained depressed despite a full recovery in core temperature and motor coordination. 

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