Volume 119, Issue 6, 08 August 2003
Index of content:
Long-range charge-transfer excited states in time-dependent density functional theory require non-local exchange119(2003); http://dx.doi.org/10.1063/1.1590951View Description Hide Description
The electrostatic attraction between the separated charges in long-range excited charge-transfer states originates from the non-local Hartree-Fock exchange potential and is, thus, a non-local property. Present-day time-dependent density functional theory employing local exchange-correlation functionals does not capture this effect and therefore fails to describe charge-transferexcited states correctly. A hybrid method that is qualitatively correct is described.
IR induced cis↔trans isomerization of 2-naphthol: Catalytic role of hydrogen-bond in the photoinduced isomerization119(2003); http://dx.doi.org/10.1063/1.1596831View Description Hide Description
An infrared laser induced cis↔transisomerization has been investigated for 2-naphthol and its hydrogen(H)-bonded cluster with in the electronic state by UV–IR double resonance excitation in a supersonic jet. A specific isomer was pumped to a X–H (X=O, C or N) stretching vibration in by a sequential UV–IR two-photon excitation, and the resultant product species were analyzed by dispersing their fluorescence. It was found that the IR excitation induces the isomerization for the H-bonded cluster with the excitation less than 3000 cm−1, while no isomerization was found to occur for bare 2NpOH even with an input energy of 3610 cm−1. The substantial reduction of the isomerization barrier height represents evidence of the catalytic nature of H-bonding in the conformational isomerization. It was also found that the isomerization efficiency is very high at low IR frequency and exhibits a marked IR frequency dependence.