Quantum belt

Recently, such carbocation formations were studied kinetically by stopped-flow laser-flash photolysis by Scaiano s group (Belt et al., 1993). The quantum yield of diphenylcarbocation formation is low (0.007). 

There are no d orbitals that correspond to principal quantum levels n = 1 and n = 2. The d orbitals ( = 2) first occur in level n = 3, The five 3d orbitals have the shapes shown in Fig. 12.21. The d orbitals have two different fundamental shapes. Four of the orbitals (d z-, dy d y and d -y ) have four lobes centered in the plane indicated in the orbital label. Note that d y and d 2-y2 are both centered in the xy plane the lobes of d -y lie along the x and y axes, but the lobes of d y lie between the axes. The fifth orbital, d has a unique shape with two lobes along the axis and a belt centered in the xy plane. The signs (phases) of the d orbital functions are indicated inside the boundary surfaces. The d orbitals for levels n> 3 look like the 3d orbitals but have larger lobes. 

The shape of the belt of stability can be understood by recognizing that the protons and neutrons can, to a good approximation, be described as if they occupy individual quantum energy levels in much the same way that electrons in multielectron atoms are described as occupying individual elecbon orbitals (Chapter 2). This shell model of the nucleus was developed independently by Maria Goeppert-Mayer and by Hans Jensen and coworkers. The shell model has been successful at explaining a number of general trends related to nuclear stability ... 

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