Femtosecond pump–probe mass spectra on the dissociative photoionization of CF3I

Imaging CF 3 I conical intersection and photodissociation dynamics with ultrafast electron diffraction

“…Here, we report the direct imaging of both conical intersection dynamics and photodissociation dynamics of gas-phase CF 3 I molecules with atomic resolution by use of ultrafast gas-phase electron diffraction (UGED). A 264.5-nm pump laser pulse initiates two photoexcitation channels: a one-photon transition to the dissociative A band and a two-photon transition to the [5pp 3 , 2 P 1/2 ](7s) (24) Rydberg state (referred to as 7s below) (25), as illustrated in Fig. 1.…”

“…We created a multidimensional movie of the structural changes in the CF 3 fragment immediately after iodide dissociation, with a precision of ±0.01 Å in bond length and ±1°in bond angle. Various groups have studied the two-photon transition into the 7s channel by using pump-probe photoelectron and photoion spectroscopy (25,(30)(31)(32). These studies identified the decay time scale and anisotropy of fragment ions, but the reaction pathway remained elusive.…”

The Study of Bond Selective Photochemistry in CH₂BrCl

“…An early approach to this problem has involved wavelength tuning of narrow-band UV laser sources to excite electronic transitions to the dissociative continua of selective bonds. As the simplest model molecules for understanding the reaction mechanism of photochemistry upon laser excitation, the photolysis of halomethanes has received much attention from both experimental [2][3][4] and theoretical viewpoints [5][6][7][8][9]. In this context, polyhaloalkanes (e.g.…”