An absorption spectrum of size-selected free cluster ions has been measured "directly" via extinction of light without relying on photodepletion/dissociation spectroscopy. The novel technique employs an ion trap and an optical cavity; cluster ions stored in an ion trap interact with photons trapped in a cavity. The storage lifetime of photons in the cavity provides "direct" observation of extinction of light (photon-trap spectroscopy, which is a generalized scheme of cavity ring-down spectroscopy). The first measurement is performed on ultraviolet absorption of Ag9 +. Temperature dependence of the spectrum is presented by cooling the ion trap down to 10 K.
!!!All Science Journal Classification (ASJC) codes