What are the normal modes of vibration for a CO2 molecule?
The four normal modes of carbon dioxide, Figure 1, are the symmetric stretch, the asymmetric stretch and two bending modes. The two bending modes have the same energy and differ only in the direction of the bending motion. Modes that have the same energy are called degenerate.
How many modes of vibration does a CO2 laser have?
The CO2 molecules consist of two oxygen atoms and a carbon atom between them. These molecules undergo three different types of vibrational oscillations. These three vibrational configurations are called vibrational modes.
What is a normal mode of vibration?
A normal mode of an oscillating system is a pattern of motion in which all parts of the system move sinusoidally with the same frequency and with a fixed phase relation. In music, normal modes of vibrating instruments (strings, air pipes, drums, etc.) are called “harmonics” or “overtones”.
How do you find the normal mode of vibration?
The required number of “normal modes” is equal to the vibrational degree of freedom available so the number of modes for a nonlinear molecule is 3N−6 and that for a linear molecule is 3N−5. Each mode has a definite frequency of vibration.
Why are there 3N 6 vibrational modes?
The remaining motions of the atoms are displacements of the atoms from their mean positions – the center of gravity does not change. These fundamental vibrations are referred to as “normal modes”. Thus, a non-linear molecule has 3N-6 normal modes.
Which vibrational modes of CO2 are IR inactive?
3: Representation of the Raman inactive bending vibration of carbon dioxide. Note that the IR active vibrations of carbon dioxide (asymmetric stretch, bend) are Raman inactive and the IR inactive vibration (symmetric stretch) is Raman active.
Which vibrational mode of CO2 has highest energy?
The symmetric stretch corresponds to both CO bonds stretching in phase, and asymmetric stretch to one CO stretching while the other compresses (this has highest frequency), and there are two degenerate bends where the OCO angle changes (lowest frequency).
Which of the laser have high efficiency?
With 450 W quasi-CW stacked laser diode bars pumping at 1064 nm, 236 W optimum output laser at 1064 nm was obtained. The optical-to-optical conversion efficiency was 52.5% and corresponding slope efficiency was 62%. This is up to now the highest slope-efficiency acquired in high power Nd:YAG ceramic laser.
Which vibrational modes of CO2 are IR active?
All three modes are IR active. For CO2 (linear molecule) there are 4 vibrational modes corresponding to symmetric stretch, antisymmetric stretch and two bends. The symmetric stretch does not change the dipole moment so it is not IR active.
Which vibrational mode in CO2 is IR inactive?
symmetric stretch
3: Representation of the Raman inactive bending vibration of carbon dioxide. Note that the IR active vibrations of carbon dioxide (asymmetric stretch, bend) are Raman inactive and the IR inactive vibration (symmetric stretch) is Raman active.