Photoinduced charge transfer in the Zn-methanol cation studied with selected-ion photofragment imaging

Abstract

The Zn+(methanol) ion molecule complex produced by laser vaporization is studied with photofragment imaging at 280 and 266 nm. Photodissociation produces the methanol cation CH3OH+ via excitation of a charge-transfer excited state. Surprisingly, excitation of bound excited states produces the same fragment via a curve crossing prior to separation of products. Significant kinetic energy release is detected at both wavelengths with isotropic angular distributions. Similar experiments are conducted on the perdeuterated methanol complex. The Zn+ cation is a minor product channel that also exhibits significant kinetic energy release. An energetic cycle using the ionization potentials of zinc and methanol together with the kinetic energy release produces an upper limit on the Zn+-methanol bond energy of 33.7 {plus minus} 4.2 kcal/mol (1.46 {plus minus} 0.18 eV).

Photodissociation Spectroscopy and Photofragment Imaging of the Fe+(Acetylene) Complex

“…In the present case, the KER max value is determined to be 0.55 ± 0.14 eV. This value is determined by applying the resolution uncertainty for the instrument (±0.14 eV) and setting the upper edge of this resolution element at the position where the signal exceeds the baseline noise, as described in previous work. − …”

“…Photofragment imaging is another approach with which to investigate the energetics and dynamics of photodissociation. − This method has recently been applied to the dissociation of mass-selected ions by several research groups. − ,− Imaging measurements detect the kinetic energy release (KER) in fragments following photodissociation, which can occur if there is excess energy above the dissociation threshold. Excess energy may be distributed among the internal vibrational, rotational, and electronic states of the fragments resulting from photodissociation in addition to the possibility of KER.…”

“…In a second experiment complementing the spectroscopy, we use photodissociation and photofragment imaging − to explore the same metal–ligand bond thermochemistry. As shown in recent work, this provides an independent determination of these energetics. − Computational studies with density functional theory (DFT) and different functionals complement these experiments.…”

Fragment imaging in the infrared photodissociation of the Ar-tagged protonated water clusters H3O+–Ar and H+(H2O)2–Ar

“…This new imaging scheme has been applied to visible/ultraviolet photodissociation reactions to study electronically excited state dynamics. [39][40][41][42][43][44][45][46][47][48][49][50][51][52] Vibrationally excited state dynamics can also be studied by infrared excitation. The first application to infrared photodissociation was for the H 2 O + -Ar complex ion.…”