Excited states

Definition

Excited states are those quantum states of an atom or a molecule with more energy than the ground state. The understanding of excited states and their relaxation to lower energy states plays an important role in spectroscopy and also lies at the heart of photochemistry.

Latest Research and Reviews

News and Comment

  • News and Views |

    Vision is initiated by photoisomerization of 11-cis retinal in the visual pigment rhodopsin — a fast and efficient process. Spectroscopic studies now demonstrate that the transition from the reactant photoexcited-state to the ground-state photoproduct, which mediates this important reaction, occurs on a sub-50-fs timescale and is vibrationally coherent.

    • Richard A. Mathies
    Nature Chemistry 7, 945–947
  • News and Views |

    Electron transfer is ubiquitous across both life and modern technologies, and thus being able to control it is an attractive goal. Now, targeted infrared excitation has been used to modulate the efficiency of electron transfer in a series of donor–bridge–acceptor molecules.

    • Igor V. Rubtsov
    Nature Chemistry 7, 683–684
  • News and Views |

    In 1972, Baird showed theoretically that the electron counting rule for aromaticity and antiaromaticity in the lowest ππ* triplet state is opposite to that in the electronic ground state. A pair of compounds that manifests this reversal in character has now been identified and characterized experimentally for the first time.

    • Henrik Ottosson
    •  & K. Eszter Borbas
    Nature Chemistry 7, 373–375
  • News and Views |

    Intense laser fields can apply strong forces to molecules, distorting molecular potentials. Now, these effects have been used to precisely control the branching ratios of a polyatomic photodissociation reaction.

    • Albert Stolow
    Nature Chemistry 6, 759–760
  • News and Views |

    Pigment assemblies with high-efficiency electronic energy transfer have recently been observed to show unusual and persistent coherence, but its origin is not fully understood. Now, a combination of 2D electronic spectroscopy and theoretical modelling has allowed the excitonic coherence signal of a strongly coupled homodimer to be isolated.

    • Vivek Tiwari
    • , William K. Peters
    •  & David M. Jonas
    Nature Chemistry 6, 173–175