Three-dimensional sliced fluorescence imaging in bulbs

Abstract

To study dynamic behaviors of molecular photodissociation processes and photoinitiated inelastic and reactive collisions in a bulb environment, a three-dimensional sliced fluorescence imaging method has been developed. This experimental method combines the sliced fluorescence imaging techniques and a double resonance spectroscopic detection scheme to acquire the central slice of state-selected Newton spheres of scattering products. To illustrate the essence and simplicity of the present method, experimental images of state-selected CN photofragments from the ICN photodissociation are presented. For other chemically significant product species with a single fluorescent excited state, an infrared-optical double resonance detection scheme warrants the present technique a general method in the study of dynamic processes in bulbs.

Determination of differential cross sections and kinetic energy release of co-products from central sliced images in photo-initiated dynamic processes

“…The volume expands from (Dr) 3 at t = 0 to roughly 4pu AB t 2 Dr at t. Thus, the number density of AB(b,J 2 ) at t drops from N AB /(Dr) 3 to N AB /4pu 2 AB t 2 Dr. An order-of-magnitude estimate dictates that subsequent reactions (eqn (2-3)) are insignificant when u AB > 1000 m/s, Dr o 5 mm, and t > 10 ns. Under these conditions which are easily fulfilled in a 3DSFI experiment, 24 product images can be attributed solely from reactions inside the crossing foci of laser beams. Because the spatial and temporal overlappings of reactants are narrowly confined in the 3DSFI experiment, the scenario in summing up various reaction events to the resultant image 11 can be greatly simplified.…”

“…The 3DSFI method, which utilizes a double resonance spectroscopic detection scheme, is ideal to explore photoinitiated, state-to-state collisional processes. 24 Beyond the state selection by laser excitation techniques, initially prepared reactants AB(b,J 2 ) are confined inside a diminutive volume at the crossing foci of the photolysis and state-selection laser beams. Even in a bulb environment, reactants AB(b,J 2 ) with well-defined speed and angular distributions can be generated in a specific quantum state inside a tiny volume (B50 mm 3 ), where the temporal span of the reactant burst is on the order of 10 ns.…”

“…Recently, we have developed a three-dimensional sliced fluorescence imaging (3DSFI) method 24 to study dynamic behaviors of molecular photodissociation processes, and photoinitiated inelastic and reactive collisions in a bulb environment. This experimental method combines the sliced fluorescence imaging techniques 25 and a double resonance spectroscopic detection scheme to acquire the central slice of state-selected Newton spheres of scattering products.…”

Sliced Fluorescence Imaging Techniques for the Study of Photo‐initiated Dynamic Processes in Bulbs

“…We have developed a three-dimensional sliced fluorescence imaging (3DSFI) 18 method which aims at dynamic studies of molecular photodissociation processes and photo-initiated inelastic and reactive collisions in a bulb environment. 3DSFI combines the sliced fluorescence imaging techniques and a double resonance spectroscopic detection scheme to acquire the central slice of state-selected Newton spheres of scattering products.…”

“…17 Our results are briefly reviewed in the next section. To push the envelope further, we developed a three-dimensional sliced fluorescence imaging method, 18 which should be suitable in the study of state-to-state inelastic collisions and photo-initiated reactive scatterings in bulbs. Its design principle and preliminary results are summarized in a later section.…”