UV‐vis spectroscopy of gas‐phase ions

Abstract

Photodissociation action spectroscopy has made a great progress in expanding investigations of gas‐phase ion structures. This review deals with aspects of gas‐phase ion electronic excitations that result in wavelength‐dependent dissociation and light emission via fluorescence, chiefly covering the ultraviolet and visible regions of the spectrum. The principles are briefly outlined and a few examples of instrumentation are presented. The main thrust of the review is to collect and selectively present applications of UV‐vis action spectroscopy to studies of stable gas‐phase ion structures and combinations of spectroscopy with ion mobility, collision‐induced dissociation, and ion–ion reactions leading to the generation of reactive intermediates and electronic energy transfer.

Cryogenic Fluorescence Spectroscopy of Ionic Fluorones in Gaseous and Condensed Phases: New Light on Their Intrinsic Photophysics

“…Although such measurements might be achievable using cavity ring-down strategies, 39,40 most gasphase spectroscopy experiments rely on measuring the appearance of a new, background-free signal generated as an "action" resulting from the absorption of light. 41,42 Nonradiative "actions" include dissociation, electron detachment, and isomerization. 43−45 There are many clear examples of action spectra recorded using these strategies that almost certainly parallel the underlying absorption spectrum; however, experimental conditions, including measurement time, 46,47 collision energy quenching, 48 non-uniform detection efficiency of ion fragments, 49 and competitive excited-state dynamical processes, can skew the correspondence.…”

Experimental techniques and terminology in gas‐phase ion spectroscopy

“…This article does not aim to cover contributions of researchers in this field, and it does not aim to explain details of all methods. For the latter, we refer the readers to numerous reviews that are devoted to the methods themselves 4–14 . We want to also stress that most of the spectroscopic methods in gas‐phase action spectroscopy originate from the previous research of neutral molecules in the gas phase.…”

“…For the latter, we refer the readers to numerous reviews that are devoted to the methods themselves. 4 , 5 , 6 , 7 , 8 , 9 , 10 , 11 , 12 , 13 , 14 We want to also stress that most of the spectroscopic methods in gas‐phase action spectroscopy originate from the previous research of neutral molecules in the gas phase. Here, however, we focus only on the gas‐phase action spectroscopy of mass‐selected ions and leave out entirely the classification of gas‐phase action spectroscopy of neutral molecules.…”

On-the-fly investigation of XUV excited large molecular ions using a high harmonic generation light source

“…Nevertheless, tremendous progress have been made in the spectroscopy of large ions. Experiments have been developed over a broad range of electromagnetic radiations, from GHz up to soft X-ray domains in order to elucidate molecular structures and electronic properties by performing rotational 8 , vibrational 9 , electronic 10 – 12 or innershell 13 action spectroscopy. The use of light in the IR, UV–Vis or UV domain as an activation method to generate efficient fragmentation has been thoroughly investigated over the past 20 years 12 , 14 , 15 , enabling the characterization of large molecular structures.…”

“…Experiments have been developed over a broad range of electromagnetic radiations, from GHz up to soft X-ray domains in order to elucidate molecular structures and electronic properties by performing rotational 8 , vibrational 9 , electronic 10 – 12 or innershell 13 action spectroscopy. The use of light in the IR, UV–Vis or UV domain as an activation method to generate efficient fragmentation has been thoroughly investigated over the past 20 years 12 , 14 , 15 , enabling the characterization of large molecular structures. These approaches were developed as complementary methods to overcome the limitations of collision induced dissociation (CID) that is based on collision with neutral gas and therefore driven by energetic barriers and statistical laws 16 – 19 .…”