Vibrational Soectroscopy

Question 1

How do atoms vibrate around equilibrium position

Answer 1

Like springs

Question 2

What is Hookes law

Answer 2

F=-k (r-re)

Question 3

What is potential energy

Answer 3

1/2k(r-re)

Question 4

What is the force constant

Answer 4

Stiffness of spring/ strength of bond

Question 5

What does potential energy mean

Answer 5

Energy due to position

Question 6

What is total energy at turning points and equilibrium distance

Answer 6

PE and KE

Question 7

If a bond is weak what is k (force constant)

Answer 7

Small

Question 8

What is vvib

Answer 8

1/2pi roots/u

Question 9

How are energy levels spaced

Answer 9

Moderately

Question 10

What region is vibrational in

Answer 10

Infra red

Question 11

What is a diatomic harmonic oscillator

Answer 11

A diatomic that obeys hookes law

Question 12

What is Ev =

Answer 12

(V+0.5)vibrational wave number

Question 13

What is V

Answer 13

Vibrational quantum number

Question 14

What is vibrational wavenumber

Answer 14

Dependent on molecule

Question 15

What is delta Ev

Answer 15

Vibrational wavenumber

Question 16

Is v ever equal to zero

Answer 16

No, so molecule always have vibrational energy

Question 17

What is the gross selection rule

Answer 17

Must change dipole on vibration

Question 18

What is the specific selection rule

Answer 18

Change in v -+1

Question 19

How many band appear

Answer 19

1

Question 20

What is a diatomic vibrating rotor

Answer 20

Both rotating and vibrating

Question 21

What approximation is used to sum the energies of vibrating rotors

Answer 21

Born Oppenheimer

Question 22

What does the spectrum look like for a vibrating rotor

Answer 22

1 band for vibrating with fine structure for rotational

Question 23

What are the J branches

Answer 23

P q and R

Question 24

What can be observed in fine structure

Answer 24

Isotope peaks

Question 25

What constant is added to the energy equation for anharmomic oscillators

Answer 25

Anharmonicoty constant

Question 26

What changes in the energy potential diagram for an a harmonic oscillator

Answer 26

Energy gaps aren’t equal and not symmetrical

Question 27

What is different about a polyatomic from a diatomic in terms of modes of vibrations

Answer 27

Polyatomic has several modes, 3N degrees of freedom with 3’translational movements

Question 28

Equations for degrees of freedom liniar and non

Answer 28

Non - 3N-6

Lin - 3N-5

Question 29

What are the types of vibrations

Answer 29

Stretching and bending

Question 30

If a molecules is symmetric what are the vibrations

Answer 30

Coupled to give symmetric

Question 31

What is an asymmetric vibration

Answer 31

Out of phase

Question 32

What is a skeletal vibrations.

Answer 32

Several or all atoms

Question 33

What is a group vibration

Answer 33

Localised on anspesific bond or grou