Gas-Phase Molecular Spectroscopy in the Past Five Decades: Bearings of the Advancements in Light Source Technologies

2015 ◽  
Vol 85 (4) ◽  
pp. 501-505
Author(s):  
Pujarini Banerjee ◽  
Tapas Chakraborty
Keyword(s):  
Gas Phase ◽  
Light Source ◽  
Molecular Spectroscopy ◽  
The Past

Simultaneous photochemical generation of ozone in the gas phase and photolysis of aqueous reaction systems using one VUV light source

1997 ◽  
Vol 35 (4) ◽  
pp. 41-48 ◽  
Author(s):  
T.M. Hashem ◽  
M. Zirlewagen ◽  
A. M. Braun
Keyword(s):  
Gas Phase ◽  
Light Source ◽  
Organic Pollutants ◽  
Vacuum Ultraviolet ◽  
Oxidative Degradation ◽  
Reaction System ◽  
Photochemical Reactions ◽  
Experimental Conditions ◽  
Photochemical Generation ◽  
Kinetics Of

A more efficient use of vacuum ultraviolet (VUV) radiation produced by an immersed Xe-excimer light source (172 nm) was investigated for the oxidative degradation of organic pollutants in aqueous systems. All emitted VUV radiation from one light source was used in two simultaneous but separate photochemical reactions: (1) photochemical generation of ozone by irradiating oxygen in the gas phase and (2) photolysis of the aqueous reaction system. The gas stream containing the generated ozone is sparged into the reaction system, thus enhancing the oxidative degradation of organic pollutants. The photochemically generated ozone in the gas phase was quantitatively analyzed, and the kinetics of the degradation of 4-chlorophenol (4-CP) and of the dissolved organic carbon (DOC) were determined under different experimental conditions. The results show that the rates of degradation of the substrate and of the DOC decrease in the order of the applied processes, VUV/O3 > O3 > VUV.

Effect of catalyst coated surface, illumination mechanism and light source in heterogeneous TiO2 photocatalysis using a mili-photoreactor for n-decane oxidation at gas phase

2019 ◽  
Vol 366 ◽  
pp. 560-568 ◽  
Author(s):  
Batuira M. da Costa Filho ◽  
Ana L.P. Araujo ◽  
Stefan P. Padrão ◽  
Rui A.R. Boaventura ◽  
Madalena M. Dias ◽  
...  
Keyword(s):  
Gas Phase ◽  
Light Source ◽  
Tio2 Photocatalysis ◽  
Coated Surface

Chapter 6. Gas-phase molecular spectroscopy

1997 ◽  
Vol 93 ◽  
pp. 187 ◽  
Author(s):  
R. F. Barrow ◽  
P. Crozet
Keyword(s):  
Gas Phase ◽  
Molecular Spectroscopy

scholarly journals In-depth structural analysis of glycans in the gas phase

2019 ◽  
Vol 10 (5) ◽  
pp. 1272-1284 ◽  
Author(s):  
Eike Mucha ◽  
Alexandra Stuckmann ◽  
Mateusz Marianski ◽  
Weston B. Struwe ◽  
Gerard Meijer ◽  
...  
Keyword(s):  
Structural Analysis ◽  
High Resolution ◽  
Gas Phase ◽  
High Throughput ◽  
Glycan Analysis ◽  
The Past

Although there have been substantial improvements in glycan analysis over the past decade, the lack of both high-resolution and high-throughput methods hampers progress in glycomics.

scholarly journals Electron-Induced Chemistry in the Condensed Phase

Atoms ◽  
2019 ◽  
Vol 7 (1) ◽  
pp. 33
Author(s):  
Jan Hendrik Bredehöft
Keyword(s):  
Gas Phase ◽  
Cross Sections ◽  
Condensed Phase ◽  
Theoretical Understanding ◽  
The Past ◽  
Long Time ◽  
The Difference ◽  
Molecule Interactions ◽  
Multi Body ◽  
Molecule Interaction

Electron–molecule interactions have been studied for a long time. Most of these studies have in the past been limited to the gas phase. In the condensed-phase processes that have recently attracted attention from academia as well as industry, a theoretical understanding is mostly based on electron–molecule interaction data from these gas phase experiments. When transferring this knowledge to condensed-phase problems, where number densities are much higher and multi-body interactions are common, care must be taken to critically interpret data, in the light of this chemical environment. The paper presented here highlights three typical challenges, namely the shift of ionization energies, the difference in absolute cross-sections and branching ratios, and the occurrence of multi-body processes that can stabilize otherwise unstable intermediates. Examples from recent research in astrochemistry, where radiation driven chemistry is imminently important are used to illustrate these challenges.

Antibonding σ* orbitals in molecular spectroscopy

1985 ◽  
Vol 63 (7) ◽  
pp. 2032-2043 ◽  
Author(s):  
M. B. Robin
Keyword(s):  
Ground State ◽  
Molecular Spectroscopy ◽  
Atomic Spectroscopy ◽  
High Symmetry ◽  
Giant Resonances ◽  
Molecular Absorption ◽  
Large Molecules ◽  
The Past ◽  
Bond Strengths

This paper discusses the role of σ* antibonding valence MO's in the electronic spectra of large molecules. Using the term value and antishielding concepts, molecular absorption patterns terminating at σ* MO's are systematized and rationalized; the frequencies of such excitations correlate with the ground-state bond strengths of the bonds giving rise to the σ* MO's. In unsaturated systems, the π → σ* and np → σ* excitations can be distinguished on the basis of their term values. Confusion in the past regarding the existence of excitations to σ* relates to the fact that σ* MO's often can be totally mixed into the surrounding sea of Rydberg levels of the same symmetry, and for all practical purposes can cease to exist except as perturbations on the Rydberg levels. For nonpenetrating Rydberg manifolds there is little or no mixing with σ* MO's of the same symmetry, setting the stage for the appearance of valence-shell excitations to σ* in high-symmetry molecules which are analogous to the d → f inner-well giant resonances of atomic spectroscopy.

scholarly journals X-ray–optical cross-correlator for gas-phase experiments at the Linac Coherent Light Source free-electron laser

2012 ◽  
Vol 100 (12) ◽  
pp. 121107 ◽  
Author(s):  
S. Schorb ◽  
T. Gorkhover ◽  
J. P. Cryan ◽  
J. M. Glownia ◽  
M. R. Bionta ◽  
...  
Keyword(s):  
Gas Phase ◽  
Light Source ◽  
Free Electron ◽  
Free Electron Laser ◽  
Coherent Light ◽  
X Ray ◽  
Linac Coherent Light Source ◽  
Coherent Light Source

Chapter 3. Gas-phase molecular spectroscopy

1979 ◽  
Vol 76 ◽  
pp. 51 ◽  
Author(s):  
M. T. Macpherson ◽  
R. F. Barrow
Keyword(s):  
Gas Phase ◽  
Molecular Spectroscopy

High-resolution interstellar spectroscopy and star formation

1981 ◽  
Vol 303 (1480) ◽  
pp. 565-579 ◽  
Keyword(s):  
Star Formation ◽  
Molecular Clouds ◽  
Molecular Spectroscopy ◽  
Active Regions ◽  
Infrared Source ◽  
Very Large Array ◽  
Dark Clouds ◽  
The Past ◽  
Different Types ◽  
Interstellar Molecular Clouds

During the past several years, high spatial and spectral resolution molecular spectroscopy has greatly contributed to our knowledge of the physics, dynamics and chemistry of interstellar molecular clouds and thus has led to a better understanding of the conditions that lead to star formation. According to their physical properties, molecular clouds can be grouped into four different types: (i) the dark clouds, (ii) the molecular clouds associated with H+ regions, (iii) the ‘protostellar’ (or maser) environment, and (iv) the molecular envelopes of late-type stars. The first three types of cloud contain generally active regions of star formation. As typical examples the properties are discussed of individual clouds such as TMC 1 and L 183 for the cold clouds, S 140 and S 106 for the warm dark clouds with embedded infrared source, and Orion A for a region with associated H+ region. In S 140, NH 3 is clumped on a scale of not more than 20", whereas recent observations towards Orion A with the Very Large Array show that NH 3 clumps on a scale smaller than 5".

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