The electronic structure of the MgY2H6þ high-pressure hydride has been investigated by means of the full potential linearized augmented plane wave method, and the stability of the octahedral and tetrahedral sites for H atoms has been discussed. The calculation models used were MgY3H8{12, corresponding to H/M = 2–3. From the calculation of the density of states for MgY3H11, it was found that the...

The QM/MM MD and free energy simulations show that serine-carboxyl peptidases (sedolisins) may stabilize the tetrahedral intermediates and tetrahedral adducts primarily through a general acid-base mechanism involving Asp (Asp164 for kumamolisin-As) rather than the oxyanion-hole interactions as in the cases of serine proteases.

By means of an EPR investigation of Mo ions introduced into NaY zeolites by solid-state reactions, the location and coordination of Mo in zeolites were investigated. Two different locations, free and distorted tetrahedral, were found. The molecular orbital coefficient, ß, and the effective charge, Q, for the MO ions in a distorted tetrahedral structure were calculated and interpreted.

Dougall's expansion is used in the expression for the volume element in tetrahedral coordinates, thereby lifting the spherical triangle restriction on the angles at the tetrahedral vertex. Application is made to the evaluation of matrix elements for the ground state of three-electron atoms.