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.

scholarly journals Photodissociation branching ratios of 13C16O and 12C18O in the vacuum ultraviolet region from 107 800 to 109 700 cm−1

2020 ◽  
Vol 637 ◽  
pp. A37 ◽  
Author(s):  
Xiaoping Chi ◽  
Pan Jiang ◽  
Qihe Zhu ◽  
Min Cheng ◽  
Hong Gao
Keyword(s):  
Vacuum Ultraviolet ◽  
Isotope Effects ◽  
Branching Ratio ◽  
Branching Ratios ◽  
Spectroscopic Studies ◽  
Ultraviolet Region ◽  
Velocity Map Imaging ◽  
Absorption Bands ◽  
Two Photon ◽  
O Isotope

In this study, we present C+ ion photofragment spectroscopic studies and photodissociation branching ratio measurements for two CO isotopologs, 13C16O and 12C18O, in the vacuum ultraviolet (VUV) region from 107 800 cm−1 (92.76 nm) to 109 700 cm−1 (91.16 nm) using a time-slice velocity-map imaging setup and a tunable VUV laser radiation source generated by the two-photon resonance-enhanced four-wave mixing technique. Several absorption bands of 12C16O in the above energy region are reinvestigated up to higher rotational levels compared with previous studies. The results are compared among 12C16O, 13C16O, and 12C18O on a state-by-state basis, and the photodissociation branching ratios for channels C(1D) + O(3P), and C(3P) + O(1D) are dramatically changed for most of the absorption bands due to the substitutions of 12C by 13C and 16O by 18O. The branching ratios of 13C16O and 12C18O are close to each other due to their similar reduced masses. The strong and selective isotope effects obtained here not only provide useful information for understanding the complicated predissociation dynamics of CO, but are also important for developing a comprehensive photochemical model for explaining the C and O isotope heterogeneities as observed in the Solar System.

Angular Distributions of EUV Generated by Electrons with 5.7 MeV Energy in a Multilayer Mo/Si Structure

2015 ◽  
Vol 1084 ◽  
pp. 280-284
Author(s):  
Sergey R. Uglov ◽  
Leonid G. Sukhikh ◽  
Artem V. Vukolov ◽  
Ivan R. Fateev
Keyword(s):  
Periodic Structure ◽  
Absorption Edge ◽  
Vacuum Ultraviolet ◽  
Transition Radiation ◽  
Angular Distributions ◽  
Ultraviolet Region ◽  
X Ray ◽  
Multilayer Mirror ◽  
Edge Filter ◽  
Vacuum Ultraviolet Region

The article considers the dynamics of the changes in the intensity and shape of the angular distributions of the backward transition radiation and quasi-monochromatic radiation emitted by the periodic structure of a multilayer mirror in a vacuum ultraviolet region for electrons with the energy of 5.7 MeV, depending on the orientation of the target. It has been shown that the dynamics of the changes in the intensity and shape of the angular distributions of the backward transition radiation and those of the periodic structure radiation observed after directing the radiation through an absorption edge filter display opposite tendencies. These opposite tendencies may be used as an indicator in the experiments aimed at detecting the effect of the periodic structure radiation in the ultraviolet region of the analog of parametric X-ray in crystals.

Photodissociation Branching Ratios of 13C16O in the Vacuum Ultraviolet Region from 102,745 to 106,360 cm−1

2020 ◽  
Vol 891 (1) ◽  
pp. 16 ◽  
Author(s):  
Xiaoping Chi ◽  
Pan Jiang ◽  
Qihe Zhu ◽  
William M. Jackson ◽  
Min Cheng ◽  
...  
Keyword(s):  
Vacuum Ultraviolet ◽  
Branching Ratios ◽  
Ultraviolet Region ◽  
Vacuum Ultraviolet Region

Luminescence Properties of Nd 3+ ‐Doped AlF 3 ‐Based Fluoride Glass in the Vacuum Ultraviolet Region

2020 ◽  
Vol 257 (8) ◽  
pp. 1900475
Author(s):  
Kohei Yamanoi ◽  
Yuki Minami ◽  
Toshihiko Shimizu ◽  
Nobuhiko Sarukura ◽  
Takahiro Murata ◽  
...  
Keyword(s):  
Vacuum Ultraviolet ◽  
Fluoride Glass ◽  
Luminescence Properties ◽  
Ultraviolet Region ◽  
Vacuum Ultraviolet Region

scholarly journals EARLINET dust observations vs. BSC-DREAM8b modeled profiles: 12-year-long systematic comparison at Potenza, Italy

2014 ◽  
Vol 14 (16) ◽  
pp. 8781-8793 ◽  
Author(s):  
L. Mona ◽  
N. Papagiannopoulos ◽  
S. Basart ◽  
J. Baldasano ◽  
I. Binietoglou ◽  
...  
Keyword(s):  
Center Of Mass ◽  
Saharan Dust ◽  
Raman Lidar ◽  
Dust Layer ◽  
Systematic Comparison ◽  
Dust Extinction ◽  
Lidar Measurements ◽  
Order Of Magnitude ◽  
Lidar Ratio ◽  
532 Nm

Abstract. In this paper, we report the first systematic comparison of 12-year modeled dust extinction profiles vs. Raman lidar measurements. We use the BSC-DREAM8b model, one of the most widely used dust regional models in the Mediterranean, and Potenza EARLINET lidar profiles for Saharan dust cases, the largest one-site database of dust extinction profiles. A total of 310 dust cases were compared for the May 2000–July 2012 period. The model reconstructs the measured layers well: profiles are correlated within 5% of significance for 60% of the cases and the dust layer center of mass as measured by lidar and modeled by BSC-DREAM8b differ on average 0.3 ± 1.0 km. Events with a dust optical depth lower than 0.1 account for 70% of uncorrelated profiles. Although there is good agreement in terms of profile shape and the order of magnitude of extinction values, the model overestimates the occurrence of dust layer top above 10 km. Comparison with extinction profiles measured by the Raman lidar shows that BSC-DREAM8b typically underestimates the dust extinction coefficient, in particular below 3 km. Lowest model–observation differences (below 17%) correspond to a lidar ratio at 532 nm and Ångström exponent at 355/532 nm of 60 ± 13 and 0.1 ± 0.6 sr, respectively. These are in agreement with values typically observed and modeled for pure desert dust. However, the highest differences (higher than 85%) are typically related to greater Ångström values (0.5 ± 0.6), denoting smaller particles. All these aspects indicate that the level of agreement decreases with an increase in mixing/modification processes.

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