The average separation between successive lines in the far-infrared absorption spectrum of hydrogen chloride gas is 20.4 cm-1. In the rotational Raman spectrum of the same molecule, this average separation (in cm-1) will be: a. 10.2 b. 20.4 c. 30.6 d.40.8

2. The following is the relative number of molecules in the vibrational states of the 1CI molecule determined from spectroscopy: Vibrational level E, E, E, E, E, E, Relative Population 100 53.5 28.6 15.3 8.2 4.4 Calculate the temperature of the sample given that the vibrational frequency is 1.15 x 10"s'.

Consider the rotational-vibrational spectrum of a diatomic molecule. Intensity a. A and B b. D and E c. A and F d. E and F 2400 Which of the following peaks belong to the P- branch? a. 18 cm-1 b. 9 cm 1 a. F Oe. C and D Estimate the value of the rotational constant B. c. 23 cm-1 d. 30 cm-¹ e. 12 cm-¹ Which peak correspond to the 1-2 transition? b. A C. E 2500 d. D e. B f. C 2600 v (cm"¹) 2700

Use the equipartition principle to estimate the value of γ = Cpm/CVm  for gaseous N2O5. Do this calculation WITH the vibrational contribution to the energy.  a. 1.07 b. 1.33 c. 1.4 d. 1.7 e. 1.5

Transitions in the rotational spectrum of the sodium chloride molecule, 23NA3ºCI, which is present in the interstellar medium, are observed at frequencies of 247.2, 260.2, 273.2, 286.2 and 299.2 GHz. Determine the bond length of a sodium chloride molecule. A. 1.09 Å В. 2.37 Å С. 5.62 Å D. 2.01 Å

What process is involved in #4?     A. external conversion   B. vibrational relaxation   C. intersystem crossing     D. internal conversion

1. The lowest energy transition (J=0 --> J=1) in teh pure rotational spectrum of 12C16O occures ar 3.8026 cm-1. Calculate the rotational constant, B in Joules) b. Calculate the bond length in meters for the diatomic in part a. c. What would be the energy of the first peak if the molecule were changed to 13C16O. Assume the bond length does not change from waht was calculated in the previous question.

10 The bond length of the CN molecule is 1.3 x 10 m. Given RAM: C = 12.0, N = 14.0, calculate (to 3 sig. fig.): (NOTE: exp = x 10 (number in bracket) 2 1. The moment of inertia, I kg m 2. The rotational constant B -1 m 3. The position (in m) of the first line in the rotational spectrum of this molecule.

11. Absorption in the = 10 vibration-rotation spectrum of 1H35CI were observed at the wavenumbers (cm-1) below. i) Assign the rotational quantum numbers and [10] ii) Use the method of combination differences to determine the rotational constants of the two vibrational levels 2998.05 2981.05 2963.35 2944.99 2925.92 2906.25 2865.14 2843.63 2821.59 2799.00 12. The rotational terms of a symmetric top, allowing for centrifugal distortion, are commonly written F(J, K) = BJJ + 1) + (à − В)к² – Ď₁J² (J + 1)² − Ճ³(J + 1)K² - DKK4 The following transition frequencies were observed for CH3F. a) Develop an expression for the wavenumbers of the allowed rotational transitions. b) Determine the values of as many constants in the expression for the rotational terms as these values permit. [15] 51.0718 GHz 102.1426 GHz 102.1408 GHz 153.2103 GHz 153.2076 GHZ

The CO molecule undergoes a rotational transition from the l=1 level to the l=2 level. Using the Table 1, calculate: a. the reduced mass of the molecule, b. the bond length of the molecule.   Table 1. Microwave Absorption Lines for Several Rotational Transitions of the CO Molecule. Rotational Transition Wavelength of Absorbed Line (m) Frequency of Absorption Line (Hz) l = 0 -> l = 1 2.60·10-3 1.15·1011 l = 1  -> l = 2 1.30·10-3 2.30·1011 l = 2 ->  l = 3 8.77·10-4 3.46·1011 l = 3 ->  l = 4 6.50·10-4 4.61·1011