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Unformatted text preview: Chem 260 Fall 2009 Assignment 8. This is an old assignment that Im reusing. You can calculate term symbols many different ways. Take a look at your notes and see how it has been suggested there. Then try the method below it involves matrices which make it easy to see what is happening (at least to me!). Notice that in the answers, some of the tables continue on a second page. As long as you come up with the same answers, it doesnt matter which method you use. See http://hyperphysics.phy-astr.gsu.edu/hbase/quantum/hydfin.html for an example of hyperfine splitting. Here is another way to think about determining term symbols. To determine the states(terms) of a given atom or ion: 1. Write down the electronic configuration (ignore closed subshell electrons) 2. Determine the number of distinct microstates that can represent that configuration. If you have e electrons in a single open subshell of 2l+1 orbitals, this value is #microstates = (2 (2l+1) )!/ e !(2 (2l+1)- e )! 3. Tabulate the number of microstates that have a given M L and M S 4. Decompose your table into terms by elimination 5. Test the total degeneracy of the resultant terms to account for all the microstates counted in parts 2 and 3 6. Determine the lowest term for the configuration by Hunds Rules. Questions for term symbols: 1. Consider a carbon atom with 2 p electrons that can go into three orbitals. There are 15 possible combinations. Determine the combinations with the highest and lowest values of M S and the highest and lowest combinations of M L . Would any of these be the ground state? 2. H(1s 1 ) 3. He(1s 2 ) 4. He(1s 1 2s 1 ) (an excited state configuration) 5. B(1s 2 2s 2 2p 1 ) 6. C(1s 2 2s 2 2p 2 ) 7. What are the atomic state term symbols resulting from the lowest energy configuration of N (1s 2 2s 2 2p 3 )?...
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