Question

The following data has been obtrained for the rotation-vibration spectrum of H¹²⁷I. Determined B₀, B_1, B_e and α_e (alpha) from this data.

Line	Frequency (cm-1)
R(0)	2242.6
R(1)	2254.8
P(1)	2217.1
P(2)	2203.8

Answer 1

In the given data B- rotation costant to be determined.

wavenumber = 2B, v =2B

speed =frequency x wavelength c=   

= c /   wave no = 1 /

1 .v = 0 , R = 0 ,B₀ = 0

2 . R = 1 , v = 2B , =c /  = 3 x 10⁸ /2254.8 = .0013 x 10⁸

v = 1 /  = 1 / .0013 x 10⁸ = 10 ^{- 5}

B₁ = v / 2 = 0.5 x 10^-5

3. P = 1 , = 2217.1 , = .0014 x 10⁸ v =714.28 x 10^{- 8}

Be = 357.14 x 10^-8

4.6B alpha = v , P =2, B = v /6 B = 714.28 x 10 ^-8 /6 = 119.04 x 10^-8