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.

ISOTOPE SHIFT OF THE NITROGEN ABSORPTION BANDS IN THE VACUUM ULTRAVIOLET REGION

1964 ◽  
Vol 42 (9) ◽  
pp. 1716-1729 ◽  
Author(s):  
M. Ogawa ◽  
Y. Tanaka ◽  
A. S. Jursa
Keyword(s):  
Isotope Shift ◽  
Vacuum Ultraviolet ◽  
Electronic States ◽  
Normal Incidence ◽  
Ultraviolet Region ◽  
Nitrogen Absorption ◽  
Absorption Bands ◽  
Quantum Numbers ◽  
Vibrational Levels ◽  
Vacuum Ultraviolet Region

The vibrational isotope shift of the nitrogen absorption bands has been studied in the 830–1000 Å region. A 3-meter normal-incidence vacuum spectrograph was used with the helium continuum as background.According to our analysis, the vibrational quantum numbers assigned to the lowest observed vibrational levels for the various electronic states of N214 are as follows: [Formula: see text], 100 824 cm−1, ν = 0; (b 1Πu), 101 455 cm−1, ν = 1; (l 1Πu), 104 146 cm−1, ν = 5; [Formula: see text], 104 366 cm−1, ν = 0; (m 1Πu), 105 350 cm−1, ν = 5 ~ 7; (o 1Πu), 105 703 cm−1, ν = 0; [Formula: see text], 106 649 cm−1, ν = 4; (p 1Πu), 108 373 cm−1, ν = 9 ~ 10; [Formula: see text], 109 833 cm−1, ν = 11 ~ 12; [Formula: see text] 110 944 cm−1, ν = 10; (s ?), 116 688 cm−1, ν > 20; and (t ?), 118 486 cm−1,[Formula: see text]. The observed isotope shift for the bands [Formula: see text], 106 381 cm−1; [Formula: see text], 108 549 cm−1; (f ?), 110 196 cm−1; [Formula: see text] 110 664 cm−1; [Formula: see text], 112 777 cm−1; (h′ ?), 114 841 cm−1; (h″ ?), 116 820 cm−1; and [Formula: see text], 118 778 cm−1 increases in this order and shows that none of these bands corresponds to a (0, 0) band.

Rotational analysis of the forbidden d3 Δi ← X1Σ+ absorption bands of carbon monoxide

1970 ◽  
Vol 48 (24) ◽  
pp. 3004-3015 ◽  
Author(s):  
G. Herzberg ◽  
T. J. Hugo ◽  
S. G. Tilford ◽  
J. D. Simmons
Keyword(s):  
Carbon Monoxide ◽  
High Resolution ◽  
Intensity Distribution ◽  
Vacuum Ultraviolet ◽  
Ultraviolet Region ◽  
Rotational Analysis ◽  
Absorption Bands ◽  
Local Perturbations ◽  
Vacuum Ultraviolet Region ◽  
Π State

The forbidden d3Δi–X1Σ+ transition of CO has been observed in absorption at high resolution in the vacuum ultraviolet region. The intensity distribution in the rotational structure of the observed bands is in conformity with the assumption that the transition occurs on account of the interaction between the d3Δ state and a 1Π state, presumably the A1Π state. Thirteen bands of the d–X system have been analyzed yielding more extensive rotational data for the d3Δi state than were previously known. A discussion of the local perturbations in the d state by the A1Π and a3Π states is included.

scholarly journals Dynamics of the Reaction S(1D) + HD, H2, and D2: Isotopic Branching Ratios and Translational Energy Release

1994 ◽  
Vol 14 (4) ◽  
pp. 235-244 ◽  
Author(s):  
Yousuke Inagaki ◽  
Sayed Mohammed Shamsuddin ◽  
Yutaka Matsumi ◽  
Masahiro Kawasaki
Keyword(s):  
Energy Release ◽  
Collision Energy ◽  
Vacuum Ultraviolet ◽  
Branching Ratio ◽  
Branching Ratios ◽  
Laser Induced Fluorescence ◽  
Translational Energy ◽  
Fluorescence Technique ◽  
Ultraviolet Laser ◽  
Reaction Proceeds

Doppler profiles of H and D atoms from the reaction S(1D) with HD and a 1:1 mixture of H2 and D2 have been measured by a laser-induced fluorescence technique with a vacuum ultraviolet laser. An isotopic channel branching ratio of φ (SD + H)/φ (SH + D) is measured to be 0.9 ± 0.1 in the reaction of S(1D) + HD at average collision energy Ecoll = 1.2 kcal/mol. In S(1D) + HD, D2, and H2, the translational energies released are almost the same, 4.6 ± 0.5 kcal/mol for H and D production channels. The measured branching ratio and translational energy release suggest that the reaction proceeds via a long-lived complex formed by insertion.

THE FORBIDDEN I1Σ−–X1Σ+ ABSORPTION BANDS OF CARBON MONOXIDE

1966 ◽  
Vol 44 (12) ◽  
pp. 3039-3045 ◽  
Author(s):  
G. Herzberg ◽  
J. D. Simmons ◽  
A. M. Bass ◽  
S. G. Tilford
Keyword(s):  
Carbon Monoxide ◽  
Selection Rule ◽  
Vacuum Ultraviolet ◽  
Ultraviolet Region ◽  
Absorption Bands ◽  
Coriolis Interaction ◽  
Dipole Radiation ◽  
Vacuum Ultraviolet Region ◽  
Vibrational Constants ◽  
Π State

The forbidden I1Σ−–X1Σ+ transition of CO has been observed in absorption at high resolution in the vacuum ultraviolet region. As expected for a 1Σ−–1Σ+ transition, the bands consist of single Q branches, in which the lines of lowest J are either missing or very weak. Although the selection rule prohibiting Σ−–Σ+ transitions is rigorous for dipole radiation at zero rotation, the I1Σ−–X1Σ+ transition can occur for higher rotational levels because of Coriolis interaction with the A1Π state, which lies very close to the I1Σ− state.Eight bands of the I–X system have been analyzed and from them the rotational and vibrational constants of the I1Σ− state have been determined. Previous information on this state was based entirely on the study of perturbations in the A1Π state. The corresponding perturbations in the I1Σ− state have now been observed. In addition, small "vibrational" perturbations in the ν = 4 and 5 levels (probably caused by interactions with the a3Π state) are found.

scholarly journals Photodissociation branching ratios of 12C16O from 110 500 to 113 045 cm−1: first observation of the C(1S) channel

2021 ◽  
Vol 647 ◽  
pp. A127
Author(s):  
Lichang Guan ◽  
Pan Jiang ◽  
Guodong Zhang ◽  
Tonghui Yin ◽  
Min Cheng ◽  
...  
Keyword(s):  
Solar Radiation ◽  
Energy Range ◽  
Vacuum Ultraviolet ◽  
Branching Ratio ◽  
Atomic Emission ◽  
Branching Ratios ◽  
Ion Imaging ◽  
Fractional Rate ◽  
Solar Photolysis ◽  
Photochemical Modelling

Carbon monoxide (CO) is one of the most abundant molecular species in comets. Its photodissociation by the solar radiation in the vacuum ultraviolet (VUV) region produces excited atomic fragments C(1D), C(1S), and O(1D), which radiate at characteristic wavelengths when they decay to lower states. The fractional rate constants for generating these fragments from CO photodissociation under the entire range of the solar radiation field are key input values in modelling the observed atomic emission intensities from comets. In this study, the branching ratios of the four lowest dissociation channels C(3P)+O(3P), C(1D)+O(3P), C(3P)+O(1D), and C(1S)+O(3P) of the 12C16O photodissociation are measured in the VUV energy range between the threshold of producing the C(1S)+O(3P) channel (~110 500 cm−1) and the ionisation energy (IE) of 12C16O (~113 045 cm−1). We measured these ratios using the VUV time-slice velocity-map ion imaging apparatus. We observe a number of high Rydberg states in the aforementioned energy range, with most of them mainly producing ground C(3P) and O(3P) atomic fragments, and only a few of them producing a significant amount of excited C(1D) or O(1D) fragments. We also observe the excited C(1S) fragment from CO photodissociation and measured its branching ratio for the first time. Based on the photodissociation branching ratios measured in the current and previous studies, we are able to estimate the relative percentages of the excited atomic fragments C(1D), C(1S), and O(1D) from the solar photolysis of 12C16O below its IE. We discuss the implications for the photochemical modelling of the CO-dominated comet C/2016 R2 (Pan-STARRS).

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

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.

Femtosecond Spectroscopic Studies of the One- and Two-Photon Excited-State Dynamics of 2,2,17,17-Tetramethyloctadeca-5,9,13-trien-3,7,11,15-tetrayne:  A Trimeric Oligodiacetylene

2006 ◽  
Vol 110 (40) ◽  
pp. 11435-11439 ◽  
Author(s):  
Grzegorz M. Balkowski ◽  
Michiel Groeneveld ◽  
Hong Zhang ◽  
Cindy C. J. Hendrikx ◽  
Michael Polhuis ◽  
...  
Keyword(s):  
Excited State ◽  
Spectroscopic Studies ◽  
Excited State Dynamics ◽  
Two Photon ◽  
The One

scholarly journals Disentangling QCD and new physics in D → πℓ+ℓ−

2021 ◽  
Vol 2021 (4) ◽  
Author(s):  
Aoife Bharucha ◽  
Diogo Boito ◽  
Cédric Méaux
Keyword(s):  
Standard Model ◽  
Branching Ratio ◽  
Branching Ratios ◽  
New Physics ◽  
Operator Product ◽  
Beyond The Standard Model ◽  
Spectral Functions ◽  
The Standard Model ◽  
Model Independent ◽  
Weak Annihilation

Abstract In this paper we consider the decay D+ → π+ℓ+ℓ−, addressing in particular the resonance contributions as well as the relatively large contributions from the weak annihilation diagrams. For the weak annihilation diagrams we include known results from QCD factorisation at low q2 and at high q2, adapting the existing calculation for B decays in the Operator Product Expansion. The hadronic resonance contributions are obtained through a dispersion relation, modelling the spectral functions as towers of Regge-like resonances in each channel, as suggested by Shifman, imposing the partonic behaviour in the deep Euclidean. The parameters of the model are extracted using e+e− → (hadrons) and τ → (hadrons) + ντ data as well as the branching ratios for the resonant decays D+ → π+R(R → ℓ+ℓ−), with R = ρ, ω, and ϕ. We perform a thorough error analysis, and present our results for the Standard Model differential branching ratio as a function of q2. Focusing then on the observables FH and AFB, we consider the sensitivity of this channel to effects of physics beyond the Standard Model, both in a model independent way and for the case of leptoquarks.

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