Concept explainers
Which of the following molecules should have pure rotational spectra?
(a) Dimethyltriacetylene,
(b) Cyanotetraacetylene,
(Such molecules have been detected in intersteller space.)
(c) Nitric oxide,
(d) Nitrogen dioxide,
(e) Sulfur tetrafluoride,
(f) Sulfur hexafluoride,
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Physical Chemistry
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- (b) The lowest frequency rotational transition of ²H³³C1 occurs at 10.92 cm1. Determine (i) The rotational constant, B, in Hz (ii) The bond lengtharrow_forwardA molecule in a gas undergoes about 1.0 × 109 collisions in each second. Suppose that (a) every collision is effective in deactivating the molecule rotationally and (b) that one collision in 10 is effective. Calculate the width (in cm³¹) of rotational transitions in the molecule.arrow_forwardConsider the diatomic molecule AB modeled as a rigid rotor (two masses separated by a fixed distance equal to the bond length of the molecule). The rotational constant of the diatomic AB is 25.5263 cm-1. (a) What is the difference in energy, expressed in wavenumbers, between the energy levels of AB with J = 10 and J = 6? (b) Consider now a diatomic A'B', for which the atomic masses are ma 0.85 mA and mB' 0.85 mB and for its bond length ra'B' = 0.913 rAB. What is the difference in energy, expressed in wavenumbers, between the energy levels of the A'B' molecule with J = 9 and J = 7?arrow_forward
- A rotating methane molecule is described by the quantum numbers J, MJ, and K. (a) For methane, how many rotational states have an energy equal to hBJ(J + 1) with J= 8? (b) Now consider chloromethane. How many rotationalstates have an energy equal to hBJ(J + 1) with J = 8?arrow_forward(c) When a gas is expanded very rapidly, its temperature can fall to a few degrees Kelvin. At these low temperatures, unusual molecules like ArHCl (Argon weakly bonded to HCl) can form on mixing. For the isotopic species Ar H$CI, the following rotational transitions were observed: J (1 → 2): 6714.44 MHz J (2 → 3): 10068.90 MHz Assume the molecule can be treated as a linear diatomic molecule (ArCl). (i) Calculate the rotational constant (B) and centrifugal distortion (D) constant for this molecule.arrow_forwardExplain the importance of the quantization of vibrational, rotational, and translational energy as it relates to the behavior of atoms and molecules.arrow_forward
- A molecule in a liquid undergoes about 1.0 × 1013 collisions in each second. Suppose that (i) every collision is effective in deactivating the molecule vibrationally and (ii) that one collision in 100 is effective. Calculate the width (in cm−1) of vibrational transitions in the molecule.arrow_forward(c) Would you expect 109AgF to have a rotational constant that is higher,lower, or equal to that of 107AgF? Explain your reasoningarrow_forwardThe 14 N160 molecule undergoes a transition between its rotational ground state and its rotational first excited state. Approximating the diatomic molecule as a rigid rotor, and given that the bond length of NO is 1.152 Angstroms, calculate the energy of the transition. As your final answer, calculate the temperature T in Kelvin, such that Ethermal = kBT equals the %3D energy of the transition between NO's rotational ground state and fırst excited state.arrow_forward
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