Theory and spectroscopy of an incarcerated quantum rotor: The infrared spectroscopy, inelastic neutron scattering and nuclear magnetic resonance of H2@C60 at cryogenic temperature

Salvatore Mamone, Judy Y.C. Chen, Rangeet Bhattacharyya, Malcolm H. Levitt, Ronald G. Lawler, Anthony J. Horsewill, Toomas Rõõm, Zlatko Bačić, Nicholas J. Turro

Research output: Contribution to journalReview articlepeer-review

Abstract

The supramolecular complex, H2@C60, represents a model of a quantum rotor in a nearly spherical box. In providing a real example of a quantum particle entrapped in a small space, the system cuts to the heart of many important and fundamental quantum mechanical issues. This review compares the predictions of theory of the quantum behaviour of H2 incarcerated in C60 with the results of infrared spectroscopy, inelastic neutron scattering and nuclear magnetic resonance. For H2@C60, each of these methods supports the quantization of translational motion of H2 and the coupling of the translational motion with rotational motion and provides insights to the factors leading to breaking of the degeneracies of states expected for a purely spherical potential. Infrared spectroscopy and inelastic neutron scattering experiments at cryogenic temperatures provide direct evidence of a profound quantum mechanical feature of H2 predicted by Heisenberg based on the Pauli principle: the existence of two nuclear spin isomers, a nuclear spin singlet (para-H2) and a nuclear triplet (ortho-H2). Nuclear magnetic resonance is capable of probing the local lattice environment of H2@C60 through analysis of the H2 motional effects on the ortho-H2 spin dynamics (para-H2, the nuclear singlet state, is NMR silent). In this review we will show how the information obtained by three different forms of spectroscopy join together with quantum theory to create a complementary and consistent picture which strikingly shows the intrinsically quantum nature of H2@C60.

Original languageEnglish (US)
Pages (from-to)938-948
Number of pages11
JournalCoordination Chemistry Reviews
Volume255
Issue number7-8
DOIs
StatePublished - Apr 2011

Keywords

  • C
  • Confined rotor
  • Fullerene
  • H@C
  • Hydrogen
  • Quantum dynamics

ASJC Scopus subject areas

  • Physical and Theoretical Chemistry
  • Inorganic Chemistry
  • Materials Chemistry

Fingerprint Dive into the research topics of 'Theory and spectroscopy of an incarcerated quantum rotor: The infrared spectroscopy, inelastic neutron scattering and nuclear magnetic resonance of H<sub>2</sub>@C<sub>60</sub> at cryogenic temperature'. Together they form a unique fingerprint.

Cite this