Computational Chemistry

(Steven Felgate) #1

Ze^2
2 e 0 nh

(4.12)

e¼1.602( 10 "^19 C,e 0 ¼8.854( 10 "^12 C^2 N"^1 m"^2 ,h¼6.626( 10 "^34 J.s
What fraction of the speed of lightc¼3.0( 108 ms"^1 ) is this value ofv?
Using the “Einstein factor”√(1"v^2 /c^2 ), calculate the mass increase factor that
this corresponds to.


Harder Questions.........................................................



  1. Is the result of the calculation in question 5 above trustworthy? Why or why not?

  2. Should relativistic effects be stronger for d or for f electrons?

  3. Why are the transition elements all metals?

  4. The simple crystal field analysis of the effect of ligands on transition metal
    d-electron energies accords well with the “deeper” molecular orbital analysis
    (see e.g. [ 99 ]). In what way(s), however, is the crystal field method unrealistic?

  5. Suggest reasons why parameterizing molecular mechanics and PM3-type pro-
    grams for transition metals presents special problems compared with parameter-
    izing for standard organic compounds.


560 8 Some “Special” Topics

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