Branching ratios and anisotropy parameters in ICl photolysis from 400 to 570 nm using slice imaging

2010 ◽  
Vol 133 (1) ◽  
pp. 014301 ◽  
Author(s):  
Peter C. Samartzis ◽  
Theofanis N. Kitsopoulos
Keyword(s):  
Branching Ratios ◽  
Anisotropy Parameters ◽  
Slice Imaging

Photodissociation of HBr molecules and clusters: Anisotropy parameters, branching ratios, and kinetic energy distributions

1999 ◽  
Vol 111 (6) ◽  
pp. 2595-2605 ◽  
Author(s):  
Reinhard Baumfalk ◽  
Udo Buck ◽  
Christian Frischkorn ◽  
Nils Hendrik Nahler ◽  
Lutz Hüwel
Keyword(s):  
Kinetic Energy ◽  
Branching Ratios ◽  
Energy Distributions ◽  
Anisotropy Parameters ◽  
Kinetic Energy Distributions

Probing of the hot-band excitations in the photodissociation of OCS at 288 nm by DC slice imaging

2004 ◽  
Vol 82 (6) ◽  
pp. 880-884 ◽  
Author(s):  
Myung Hwa Kim ◽  
Wen Li ◽  
Suk Kyoung Lee ◽  
Arthur G Suits
Keyword(s):  
Cross Section ◽  
Molecular Beam ◽  
Potential Surface ◽  
Imaging Technique ◽  
Branching Ratio ◽  
Translational Energy ◽  
Hot Band ◽  
Anisotropy Parameters ◽  
Slice Imaging ◽  
Central Slice

The photodissociation dynamics of OCS at 288 nm has been investigated using the DC (direct current) slice imaging technique, which is a recently developed high-resolution "slicing" approach that directly measures the central slice of the photofragment distribution in imaging experiments. By analyzing a DC sliced image of S(1D2) photofragments we observe dissociation originating from OCS molecules excited up to v2 = 4 in the molecular beam. The measured translational energy distribution was used to determine the branching ratio for the contribution from each initial bending state (0 v2 0) of OCS and relative photodissociation cross section ratios compared to v2 = 1. Large negative anisotropy parameters determined as a function of the S(1D2) fragment recoil speed indicate that the photodissociation of OCS at 288 nm occurs exclusively from the 11A′′(1Σ–) bending excited potential surface that can be accessed through a perpendicular transition.Key words: DC slicing imaging, OCS, photodissociation, hot-band excitation.

O(3Pj) atom formation from photodissociation of ozone in the visible and ultraviolet region

1994 ◽  
Vol 72 (3) ◽  
pp. 637-642 ◽  
Author(s):  
Sayed Mohammed Shamsuddin ◽  
Yousuke Inagaki ◽  
Yutaka Matsumi ◽  
Masahiro Kawasaki
Keyword(s):  
Vacuum Ultraviolet ◽  
Center Of Mass ◽  
Visible Region ◽  
Branching Ratios ◽  
Angular Distributions ◽  
Ultraviolet Region ◽  
Relative Speed ◽  
Potential Surfaces ◽  
Anisotropy Parameters ◽  
532 Nm

The photodissociation of ozone at 266, 308, and 532 nm has been studied for [Formula: see text] probing O(3Pj) atomic photofragments by a vacuum ultraviolet laser-induced fluorescence method. Angular distributions and average kinetic energies are determined by measuring Doppler profiles of the O(3Pj) photofragments. Anisotropy parameters β for the angular distributions are 0.81 ± 0.10 at 266 nm, 0.60 ± 0.10 at 308 nm, and −0.68 ± 0.09 at 532 nm. These values are consistent with the assignment of the photoexcited states, that is, 1B2 in the ultraviolet and 1B1 in the visible region. Average center-of-mass translational energies are 44, 38, and 21 kcal/mol for photodissociation at 266, 308, and 532 nm, respectively. The j-branching ratios of O(3Pj) produced from the photodissociation at 266 nm are (j = 2)/(j = 1)/(j = 0) = (0.55 ± 0.03)/(0.32 ± 0.03)/(0.12 ± 0.03), which are close to the state degeneracy (2j + 1) ratios. At 308 and 532 nm the branching ratios are (j = 2)/(j = 1)/(j = 0) = (0.66 ± 0.03)/(0.27 ± 0.03)/(0.09 ± 0.01) and (0.74 ± 0.03)/(0.20 ± 0.02)/(0.05 ± 0.01), respectively. Population of the j = 2 level increases with decreasing photon energies. The ratios obtained are discussed in terms of the adiabaticity of the potential surfaces during bond breakup as a function of the relative speed of separation.

Convergence Properties of Quasiclassical Trajectory Calculations on Dynamics of Autoionization Event in He(23S)-D2 Penning Ionization

1997 ◽  
Vol 62 (2) ◽  
pp. 154-171 ◽  
Author(s):  
Jan Vojtík ◽  
Richard Kotal
Keyword(s):  
Branching Ratios ◽  
Classical Trajectory ◽  
Vibrational States ◽  
Penning Ionization ◽  
Trajectory Calculations ◽  
Quantum Mechanical Treatment ◽  
Total Ionization ◽  
Vibrational Levels ◽  
Degree Of Convergence ◽  
Product Branching

An analysis of the degree of convergence of theoretical pictures of the dynamics of the autoionization event He(23S)-D2(v" = 0) -> [He...D2+(v')] + e is presented for a number of batches of Monte Carlo calculations differing in the number of the trajectories run. The treatment of the dynamics consists in 2D classical trajectory calculations based on static characteristics which include a quantum mechanical treatment of the perturbed D2(v" = 0) and D2+(v') vibrational motion. The vibrational populations are dynamical averages over the local widths of the He(23S)-D2(v" = 0) state with respect to autoionization to D2+(...He) in its v'th vibrational level and the Penning electron energies are related to the local differences between the energies of the corresponding perturbed D2(v" = 0)(...He*) and D2+(v')(...He) vibrational states. Special attention is paid to the connection between the requirements on the degree of convergence of the classical trajectory picture of the event and the purpose of the calculations. Information is obtained regarding a scale of the trajectory calculations required for physically sensible applications of the model to an interpretation of different type of experiments on the system: total ionization cross section measurements, Penning ionization electron spectra, subsequent 3D classical trajectory calculations of branching ratios of the products of the postionization collision process, and interpretation of electron ion coincidence measurements of the product branching ratios for individual vibrational levels of the nascent Penning ion.

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