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,
Want to see the full answer?
Check out a sample textbook solutionChapter 14 Solutions
Physical Chemistry
- 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_forwardCalculate the relative number of molecules in the J = 1 and J = 2 rotational states of HCI at 27 \deg C. (I = 2.643 x 1047 kg m^2).arrow_forwardRotational spectra are affected slightly by the fact that different isotopes have different masses. Suppose a sample of the common isotope 1H35Cl is changed to 1H37Cl. (a) By what fraction is the molecule’s rotational inertia different? (The bond length is 0.127 nm in each case.) (b) What is the change in energy of theℓ = 1 to theℓ = 0 transition if the isotope is changed?arrow_forward
- The rotational constant for CO is 1.9314 cm−1 and 1.6116 cm−1 in the ground and first excited vibrational states, respectively. By how much does the internuclear distance change as a result of this transition?arrow_forwardCalculate the relative populations of the J = 2 and J = 1 rotational levels of HCI at 25 oC. For HCI the rotational constant is B =318.0 GHz.arrow_forwardThis question pertains to rotational spectroscopy. Which of the following molecules would have a pure rotational spectrum and why? HCl, N2O, O3, SF4 What information is obtained from the rotational spectrum of a diatomic molecule and how can it be used to determine the bond length of a diatomic molecule? What is the selection rule for rotational spectroscopy? The rotational constant of 127I35Cl is 3.424 GHz. Calculate the ICl bond length.arrow_forward
- The NOF molecule is an asymmetric rotor with rotational constants 3.1752 cm−1, 0.3951 cm−1, and 0.3505 cm−1. Calculate the rotational partition function of the molecule at (i) 25 °C, (ii) 100 °C.arrow_forwardThe vibrational wavenumber of the oxygen molecule in its electronic ground state is 1580 cm−1, whereas that in the excited state (B 3Σu−), to which there is an allowed electronic transition, is 700 cm−1. Given that the separation in energy between the minima in their respective potential energy curves of these two electronic states is 6.175 eV, what is the wavenumber of the lowest energy transition in the band of transitions originating from the v = 0 vibrational state of the electronic ground state to this excited state? Ignore any rotational structure or anharmonicity.arrow_forwardThe moment of inertia of CH4 can be calculated from the expression I=8/3 mHR2 where R is the C-H bond length (109 angstrom or 109 x 1012 m). a. What is the lowest possible rotational energy of the CH4 molecule and what is the value of quantum number l associated with that rotational energy? b. Calculate the rotational energy of the molecule in the first excited state (when quantum number l = 1). c. Determine the degeneracy of the first excited state. Explain what is meant by rotational energy degeneracy.arrow_forward
- Explain the importance of the quantization of vibrational, rotational, and translational energy as it relates to the behavior of atoms and molecules.arrow_forwardConsider the rotational temperatures of the following hetero diatomic molecules: θr(CO) = 2.1 K, θr(HF) = 30.2 K. In which case would the classical approximation be accurate? Justify your answer.arrow_forwardConsider the rotational spectrum of a linear molecule at 298 K with a moment of inertia of 1.23×10−461.23\times10^{-46}1.23×10−46 kg m2 . (a) What is the frequency for the transition from J = 2 to J = 3? (b) What is the most populated rotational level for this molecule? Would the transition in (a) give the most intense signal in the rotational spectrum?arrow_forward
- ChemistryChemistryISBN:9781305957404Author:Steven S. Zumdahl, Susan A. Zumdahl, Donald J. DeCostePublisher:Cengage LearningChemistryChemistryISBN:9781259911156Author:Raymond Chang Dr., Jason Overby ProfessorPublisher:McGraw-Hill EducationPrinciples of Instrumental AnalysisChemistryISBN:9781305577213Author:Douglas A. Skoog, F. James Holler, Stanley R. CrouchPublisher:Cengage Learning
- Organic ChemistryChemistryISBN:9780078021558Author:Janice Gorzynski Smith Dr.Publisher:McGraw-Hill EducationChemistry: Principles and ReactionsChemistryISBN:9781305079373Author:William L. Masterton, Cecile N. HurleyPublisher:Cengage LearningElementary Principles of Chemical Processes, Bind...ChemistryISBN:9781118431221Author:Richard M. Felder, Ronald W. Rousseau, Lisa G. BullardPublisher:WILEY