Vibrational Energy within Electronic (5)

Question 1

What does the Born-Oppenheimer Approximation say about the energies involved in rotational, vibrational, and electronic transitions?

Answer 1

to the first approximation, they may be considered completely independent

Question 2

Why can rotational energy transitions be ignored when discussing electronic transitions?

Answer 2

they are relatively small

Question 3

How are vibrational energy levels specified within an electronic energy state?

Answer 3

spectroscopic shorthand

Question 4

What is the symbol used to denote a vibrational energy level within a ground electronic state?

Answer 4

’’

Question 5

What is the symbol used to denote a vibrational energy level within an excited electronic state?

Answer 5

’

Question 6

What are the selection rules for electronic transitions?

Answer 6

no rule for vibrational quantum number when molecule undergoes electronic transition; every v’’ to v’ has some probability

Question 7

From what vibrational level do most electronic absorptions begin?

Answer 7

v’’ = 0

Question 8

What does the Franck-Condon principle say about internuclear motions during an electronic absorption?

Answer 8

distance can be regarded as fixed

Question 9

What does the frank-condos principle say about the transitions between wave functions of two vibrational states?

Answer 9

transition is more probable if it begins in the middle of ground v’’ = 0 and terminates toward either end of the excited v’ level