In the near Infared spectrum of carbon monoxide there is an intense band at 2144 cm. Calculate the fundamental vibration frequency of CO, the force constant and zero point energy



Answer :

Answer:

Explanation:

To calculate the fundamental vibration frequency, force constant, and zero-point energy of carbon monoxide (CO), we can use the information provided and apply some fundamental equations from molecular spectroscopy.

1. Fundamental Vibration Frequency

The band at 2144 cm

1

−1

 corresponds to the vibrational transition of CO. The fundamental vibration frequency

ν in Hz can be calculated using the wavenumber

ˉ

ν

ˉ

:

=

ˉ

×

ν=

ν

ˉ

×c

where:

ˉ

=

2144

cm

1

ν

ˉ

=2144cm

−1

c is the speed of light in cm/s (

2.998

×

1

0

10

cm/s

c≈2.998×10

10

cm/s)

=

2144

cm

1

×

2.998

×

1

0

10

cm/s

ν=2144cm

−1

×2.998×10

10

cm/s

=

6.435

×

1

0

13

Hz

ν=6.435×10

13

Hz

2. Force Constant

The force constant

k can be calculated using the formula:

=

(

2

)

2

k=μ(2πν)

2

where:

μ is the reduced mass of the CO molecule.

ν is the fundamental vibration frequency in Hz.

The reduced mass

μ is calculated using:

=

1

×

2

1

+

2

μ=

m

1

+m

2

m

1

×m

2

For CO:

Mass of carbon (

m

C

) = 12 amu

Mass of oxygen (

m

O

) = 16 amu

=

12

×

16

12

+

16

=

192

28

6.857

amu

μ=

12+16

12×16

=

28

192

≈6.857amu

Convert this mass into kg (1 amu =

1.660539

×

1

0

27

kg

1.660539×10

−27

kg):

=

6.857

×

1.660539

×

1

0

27

1.141

×

1

0

26

kg

μ=6.857×1.660539×10

−27

≈1.141×10

−26

kg

Now calculate

k:

=

(

2

)

2

k=μ(2πν)

2

=

1.141

×

1

0

26

×

(

2

×

6.435

×

1

0

13

)

2

k=1.141×10

−26

×(2π×6.435×10

13

)

2

1.141

×

1

0

26

×

(

4.038

×

1

0

14

)

2

k≈1.141×10

−26

×(4.038×10

14

)

2

1.141

×

1

0

26

×

1.631

×

1

0

29

k≈1.141×10

−26

×1.631×10

29

1.867

×

1

0

3

N/m

k≈1.867×10

3

N/m

3. Zero-Point Energy

The zero-point energy (ZPE) can be calculated using:

0

=

1

2

E

0

=

2

1

where

h is Planck’s constant (

6.626

×

1

0

34

J s

6.626×10

−34

J s) and

ν is the frequency in Hz.

0

=

1

2

×

6.626

×

1

0

34

×

6.435

×

1

0

13

E

0

=

2

1

×6.626×10

−34

×6.435×10

13

0

2.14

×

1

0

20

J

E

0

≈2.14×10

−20

J

0

0.134

eV

E

0

≈0.134eV

Summary

Fundamental Vibration Frequency:

6.435

×

1

0

13

Hz

6.435×10

13

Hz

Force Constant:

1.867

×

1

0

3

N/m

1.867×10

3

N/m

Zero-Point Energy:

2.14

×

1

0

20

J

2.14×10

−20

J (or

0.134

eV

0.134eV)