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Chem423_problemset2_s08 - set of term symbols for the...

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Chem 423 Spring 2008 Problem Set 2 Due 11:00 AM, Friday, April 11, 2008 In order to receive full credit, all work must be shown. 1 . In high-temperature sources, sodium atoms emit a doublet with an average wavelength of 1138 nm. The transition responsible for this is from the 4s to the 3p state. Determine all of the term symbols for these two states and the degeneracy of each state. Calculate the Boltzmann distribution for these states for an inductively coupled plasma at 9000 K. 2. The two figures (attached) are the results of a number of graphite-furnace AA runs performed by graduate students. In both figures, peak area has been plotted against Pb concentration as a function of either ashing temperature or atomization temperature. Provide a detailed explanation of the results. 3. The lowest triplet state manifold in calcium is 1.886 eV above the ground-state and has three J sublevels, J = 0, 1, and 2. What is the electron configuration and the full
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Unformatted text preview: set of term symbols for the lowest triplet state manifold? Of course, emission from this triplet state manifold to the ground state is extremely weak. Why is that? What is the term symbol of the ground state for calcium? What are the population ratios of the levels in this manifold to the ground state at thermal equilibrium in a plasma with a temperature of 40,000 K? 4. The table below records peak area as a function of ashing, or pretreatment, temperature for an aqueous sample of Pb 2+ using the graphite-furnace AA. Temperature ( o C) neat sample w/NH 4 H 2 PO 4 matrix modifier 600 0.24 0.24 700 0.24 0.24 800 0.24 0.24 900 0.21 0.24 1000 0.15 0.21 1100 0.04 0.17 1200 0.02 0.13 What is the effect of adding the matrix modifier? How does the matrix modifier work? Provide other reasons for the use of matrix modifiers in graphite-furnace AA. 5. The Ar +-laser is a four-level system. Draw the energy level diagram for a laser of this type....
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