Electronic energy removal

TABLE 10. Vibrational and Electronic Energy Removal Rate Constants and Cross Sections for the B2C0 (A, lA2) in the 4l Level at 23°Ca... 

The orbitals from which electrons are removed can be restricted to focus attention on the correlations among certain orbitals. For example, if the excitations from the core electrons are excluded, one computes the total energy that contains no core correlation energy. The number of CSFs included in the Cl calculation can be far in excess of the number considered in typical MCSCF calculations. Cl wavefimctions including 5000 to 50 000 CSFs are routine, and fimctions with one to several billion CSFs are within the realm of practicality [53]. 

If we continue to remove electrons from aluminum, we discover a very large increase in ionization energy when the fourth electron is removed. Again this is because the fourth electron must be withdrawn from a 2p orbital, an orbital much lower on the energy level diagram. We conclude that three electrons, the two 35 and the one 3p, are more easily removed than the others. Since aluminum has three easily removed electrons, aluminum is said to have three valence electrons. 

The third ionization energy of magnesium is more than ten times the first ionization energy. This large increase occurs because the third ionization removes a core electron (2 p) rather than a valence electron (3. ). Removing core electrons from any atom requires much more energy than removing valence electrons. The second ionization... 

In the liquid state, the molecules are still free to move in three dimensions but stiU have to be confined in a container in the same manner as the gaseous state if we expect to be able to measure them. However, there are important differences. Since the molecules in the liquid state have had energy removed from them in order to get them to condense, the translational degrees of freedom are found to be restricted. This is due to the fact that the molecules are much closer together and can interact with one another. It is this interaction that gives the Uquid state its unique properties. Thus, the molecules of a liquid are not free to flow in any of the three directions, but are bound by intermolecular forces. These forces depend upon the electronic structure of the molecule. In the case of water, which has two electrons on the ojQ gen atom which do not participate in the bonding structure, the molecule has an electronic moment, i.e.- is a "dipole". 

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