Lab9.
Prelab Questions.
Questions you NEED
to answer in a written form before the Lab in
your notebook.
- How many normal vibrational modes are in CO2,
and C2H2 molecules? Which of them
do you expect to see in IR absorption? in Raman spectra?
- Calculate Be for ground
state of 12CO2, H35Cl, D35Cl,
12C2H2 and 12C2D2
using Eq.(6) in its convenient explicit expression:
| Be
= |
h |
|
16.8576314 |
cm-1 |
|
= |
|
| 8p2Ic |
|
I(amu Å2) |
where masses are
measured in atomic units and distances in Å ( 1Å
= 10-8 cm). Take for CO2: rCO = 1.16 Å; for
HCl: rHCl
= 1.275 Å, for acetylene: RCC
= 1.2024 Å, RCH
= 1.0625 Å. Masses in atomic units are: H = 1.007825; D
= 2.014102; 35Cl = 34.968853. Use either
Eq.(4) or (24) for calculation of I.
-
What kind of questions you MAY be
asked before the Lab.
- Explain Eq.(5) in introduction:
which terms correspond to the energy of a harmonic
oscillator, a rigid rotor, anharmonicity, centrifugal
stretching, and the interaction
between vibration and rotation.
- Describe the selection rules for vibration-rotational
transitions
- What is an overtone, a hot band and a fundamental
transition?
Last updated on 04/19/99
Email: snsm@nmsu.edu