Question

1B. Next we zoom in on the lowest energy absorption band Absorbance of CO 2110 2140 Wavenumbers cm 2170 2180 2100 2120 2130 2150 2160 On the graph, the label P and R branches of the spectrum Fill in the table below Branch Label Starting J Frequency Final J P(2) P(3) R(0 R(2) Using the absorption energies of the peaks in your table, estimate Bo and B1 How much does the CO bond length change at v 1 vs v 0? iv

plz...

Answer 1

i) P branch is due to transition of
J-1
and R branch for $\Delta J=+1$ , $\Delta J$ is the difference of two consecutive rotational energy level.

P lines lie left to 2140 cm^-1 wave number and R lines is to the right to 2146.8 cm^-1( though the values are not seen clearly).

ii) frequency=velocity of light*wave number

branch level	frequency	starting J	final J
P(1)	10 13 2140.7 × 3 × 10" H 6.42 × 10	1	0
P(2)	13 6.40 × 10- 2136.3 × 3 × 10" H	2	1
P(3)	2131.4 × 3 × 1010Hz = 6.39 × 1013H:	3	2
R(0)	13 6.44 × 10" 2146.3 × 3 × 10" H	0	1
R(1)	13 6.45 × 10Hz 2150.7 × 3 × 1010 Hz	1	2
R(2)	13 6.46 × 10Hz 2151.1 × 3 × 1010 Hz	2	3

[please check the frequency values from the spectra, they are not visible properly, I tried my best though.]