Rotational spectroscopy of the atmospheric photo-oxidation product o-toluic acid and its monohydrate

2016 ◽  
Vol 18 (1) ◽  
pp. 448-457 ◽  
Author(s):  
Elijah G. Schnitzler ◽  
Brandi L. M. Zenchyzen ◽  
Wolfgang Jäger
Keyword(s):  
Oxidation Product ◽  
Minimum Energy ◽  
Rotational Spectroscopy ◽  
Rotational Spectra ◽  
Photo Oxidation

Pure rotational spectra of an atmospheric photo-oxidation product, o-toluic acid, and its monohydrate were measured, and the minimum energy conformers of both species were identified.

Rotational spectroscopy of methyl benzoylformate and methyl mandelate: structure and internal dynamics of a model reactant and product of enantioselective reduction

2015 ◽  
Vol 17 (34) ◽  
pp. 21942-21949 ◽  
Author(s):  
Elijah G. Schnitzler ◽  
Mohammad Reza Poopari ◽  
Yunjie Xu ◽  
Wolfgang Jäger
Keyword(s):  
Minimum Energy ◽  
Rotational Spectroscopy ◽  
Internal Dynamics ◽  
Rotational Spectra ◽  
Enantioselective Reduction ◽  
Methyl Benzoylformate ◽  
Methyl Rotation

Rotational spectra of a prochiral ester, methyl benzoylformate, and the product of its enantioselective reduction, (R)-(–)-methyl mandelate, were measured, and minimum energy conformers and methyl rotation barriers were determined.

scholarly journals Characterization of a photoproduct of 7,12-dimethylbenz[a]anthracene and its effects on chick-embryo cells in culture

1977 ◽  
Vol 164 (3) ◽  
pp. 481-486 ◽  
Author(s):  
D Warshawsky ◽  
E Kerns ◽  
M J Bissell ◽  
M Calvin
Keyword(s):  
Chick Embryo ◽  
Dna Synthesis ◽  
Oxidation Product ◽  
Biological Effects ◽  
Cell Number ◽  
Resonance Spectroscopy ◽  
Morphological Transformation ◽  
Morphological Alterations ◽  
Photo Oxidation ◽  
Embryo Cells

A common impurity of 7,12-dimethylbenz[alpha]anthracene was more effective than 7,12-dimethylbenz[alpha]anthracene in inducing morphological alterations, and in causing an increase in glucose uptake, DNA synthesis and cell number in chick-embryo fibroblasts. Gradual morphological transformation follows the increase in DNA synthesis after 2 days when either primary or secondary cultures are treated with 3 microgram of the compound/ml. The compound, isolated from 7,12-dimethylbenz[alpha]anthracene by alumina column chromatography, was characterized by t.l.c., mass spectroscopy, carbon-hydrogen analysis, u.v. and nuclear-magnetic-resonance spectroscopy and thermal decomposition. It was the photo-oxidation product of 7,12-dimethylbenz[alpha]anthracene, 7,12-epidioxy-7,12-dimethylbenz[alpha]anthracene. It is suggested that some of the biological effects observed after treatment of cultures with 7,12-dimethylbenz[alpha]anthracene may be due in part to the presence of the photo-oxidation product.

The Photo-Oxidation of Polypropylene Monofilaments

1977 ◽  
Vol 47 (6) ◽  
pp. 423-428 ◽  
Author(s):  
A. Garton ◽  
D. J. Carlsson ◽  
P. Z. Sturgeon ◽  
D. M. Wiles
Keyword(s):  
Mechanical Properties ◽  
Surface Layer ◽  
Uv Irradiation ◽  
Oxidation Product ◽  
Uv Exposure ◽  
Thin Surface Layer ◽  
Elongation At Break ◽  
Photo Oxidation ◽  
Oriented Samples ◽  
Oriented Polypropylene

The elongation-at-break of highly-oriented polypropylene monofilaments is much less affected by photo-oxidation build-up than undrawn or partially-oriented filaments. This appears to result from the very poor lateral cohesion of the fibril bundles in the highly-oriented filament, limiting restructuring and cracking to a thin surface layer. For less-oriented samples photo-oxidation-induced restructuring of the surface layer results in deep cracks that can propagate under stress, greatly embrittling the sample. Areas of filaments cold drawn by, for example, bending or stretching deteriorate very rapidly on uv irradiation as a result of strain-induced chromophore formation, and fracture occurs first at these points. Oxidation-product levels (either hydroperoxide or carbonyl) are shown to be an unreliable index of the extent of deterioration of mechanical properties resulting from uv exposure.

The axial/equatorial conformational landscape and intramolecular dispersion: new insights from the rotational spectra of monoterpenoids

2019 ◽  
Vol 21 (47) ◽  
pp. 26111-26116 ◽  
Author(s):  
Donatella Loru ◽  
Annalisa Vigorito ◽  
Andreia F. M. Santos ◽  
Jackson Tang ◽  
M. Eugenia Sanz
Keyword(s):  
Quantum Chemistry ◽  
Rotational Spectroscopy ◽  
Theoretical Methods ◽  
Rotational Spectra ◽  
Quantum Chemistry Calculations ◽  
Conformational Landscape

Using rotational spectroscopy and quantum chemistry calculations, we show that intramolecular dispersion stabilises the axial conformers of monoterpenoids, and that an accurate account of these interactions is challenging for theoretical methods.

scholarly journals Generation and structural characterization of Ge carbides GeCn (n = 4, 5, 6) by laser ablation, broadband rotational spectroscopy, and quantum chemistry

2019 ◽  
Vol 21 (35) ◽  
pp. 18911-18919
Author(s):  
Kin Long Kelvin Lee ◽  
Sven Thorwirth ◽  
Marie-Aline Martin-Drumel ◽  
Michael C. McCarthy
Keyword(s):  
Fourier Transform ◽  
Laser Ablation ◽  
Structural Characterization ◽  
Quantum Chemical ◽  
Microwave Spectroscopy ◽  
Rotational Spectroscopy ◽  
Chirped Pulse ◽  
Rotational Spectra ◽  
High Level

Rotational spectra of three Ge carbides, linear GeC4, GeC5, and GeC6 have been observed using chirped pulse and cavity Fourier transform microwave spectroscopy via laser ablation, guided by new high-level quantum chemical calculations.

Theoretical Study of Rotational Spectroscopy of Acetonitrile-d3in the Ground and Different Excited Vibrational States

2008 ◽  
Vol 5 (2) ◽  
pp. 201-218
Author(s):  
Motamedi Masoud ◽  
Moradi Parinaz
Keyword(s):  
Least Squares ◽  
Millimeter Wave ◽  
Theoretical Study ◽  
Rotational Spectroscopy ◽  
Accuracy Analysis ◽  
Centrifugal Distortion ◽  
Vibrational States ◽  
Rotational Spectra ◽  
Centrifugal Distortion Constants

The millimeter-wave rotational spectra of the ground and excited vibrational states v8= 1 and v8= 2 of the symmetric top molecule CD3CN have been analyzed again. Thel= ± 1 in v8=1,l= 0 andl= ± 2 series in v8= 2 states have been assigned respectively. The assignment and analysis of the measurements with a least – squares procedure have made it possible to obtain the rotational, quartic and sextic centrifugal distortion constants with more reliable and higher accuracy. Analysis of the v8= 2 state gave the following rotational parameters: Aζ = 62218.96 MHz and xll= 87527.70 MHz. Investigation in v8= 2 state indicates thatl-resonance is observed for this molecule aroundk=xℓℓ+(A−B)−2AζAζ−(A−B)≈4.

scholarly journals Observation of 2-methyltetrols and related photo-oxidation products of isoprene in boreal forest aerosols from Hyytiälä, Finland

2005 ◽  
Vol 5 (3) ◽  
pp. 2947-2971 ◽  
Author(s):  
I. Kourtchev ◽  
T. Ruuskanen ◽  
W. Maenhaut ◽  
M. Kulmala ◽  
M. Claeys
Keyword(s):  
Boreal Forest ◽  
Atmospheric Chemistry ◽  
Oxidation Product ◽  
Unsaturated Fatty Acids ◽  
Oxidation Products ◽  
Conifer Forest ◽  
Aerosol Formation ◽  
Summer Period ◽  
Photo Oxidation ◽  
Pinic Acid

Abstract. Oxidation products of isoprene including 2-methyltetrols (2-methylthreitol and 2-methylerythritol), 2-methylglyceric acid and triol derivatives of isoprene (2-methyl-1,3,4-trihydroxy-1-butene (cis and trans) and 3-methyl-2,3,4-trihydroxy-1-butene) have been detected in boreal forest PM1 aerosols collected at Hyytiälä, southern Finland, during a 2004 summer period, at significant atmospheric concentrations (in total 51 ng m-3 in summer versus 0.46 ng m-3 in fall). On the basis of these results, it can be concluded that photo-oxidation of isoprene is an important atmospheric chemistry process that contributes to secondary organic aerosol formation during summer in this conifer forest ecosystem. In addition to isoprene oxidation products, malic acid, which can be regarded as an end-oxidation product of unsaturated fatty acids, was also detected at high concentrations during the summer period (46 ng m-3 in summer versus 5.2 ng m-3 in fall), while levoglucosan, originating from biomass burning, became relatively more important during the fall period (29 ng m-3 in fall versus 10 ng m-3 in summer). Pinic acid, a major photo-oxidation product of α-pinene in laboratory experiments, could only be detected at trace levels in the summer PM1 aerosol samples from Hyytiälä, suggesting that further oxidation of pinic acid occurs and/or that different oxidation pathways are followed. We hypothesize that photo-oxidation of isoprene may participate in the early stages of new particle formation, a phenomenon which has been well documented in the boreal forest environment.

scholarly journals Decoding Pure Rotational Molecular Spectra for Asymmetric Molecules

2013 ◽  
Vol 2013 ◽  
pp. 1-10 ◽  
Author(s):  
S. A. Cooke ◽  
P. Ohring
Keyword(s):  
Rotational Constant ◽  
Rotational Spectroscopy ◽  
Molecular Spectra ◽  
Web Page ◽  
Mobile Web ◽  
Molecular Systems ◽  
Rotational Spectra ◽  
Constant Determination ◽  
Line Positions ◽  
Spectral Assignment

Rotational spectroscopy can provide insights of unparalleled precision with respect to the wavefunctions of molecular systems that have relevance in fields as diverse as astronomy and biology. In this paper, we demonstrate how asymmetric molecular pure rotational spectra may be analyzed “pictorially” and with simple formulae. It is shown that the interpretation of such spectra relies heavily upon pattern recognition. The presentation of some common spectral line positions in near-prolate asymmetric rotational spectra provides a means by which spectral assignment, and approximate rotational constant determination, may be usefully explored. To aid in this endeavor we have created a supporting, free, web page and mobile web page.

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