Simultaneous measurements of visible (400-700 nm) and infrared (3.4 microm) NO(2) absorption

Laboratory measurements of NO(2) absorption were obtained in the visible (400-700 nm) and mid-infrared (3.4 mum) regions simultaneously using SCISAT-1's ACE-FTS (atmospheric chemistry experiment-Fourier transform spectrometer) and MAESTRO (measurement of aerosol extinction in the stratosphere and troposphere retrieved by occultation) spectrometers. An intercomparison of these measurements was used to verify the consistency between the HITRAN 2004 3.4-mum band strengths and the strengths of three different visible cross section data sets. These measurements should be of interest to the remote-sensing community, since NO(2) measurements obtained by infrared-range instruments are often compared to those obtained by visible-range instruments without accurate knowledge of the consistency between the visible and infrared absorption coefficients. Two significant results were obtained in this study: (1) A 0.5% agreement was found between the HITRAN 2004 line strengths and the Vandaele et al. (Vandaele, A. C.; Hermans, C.; Fally, S.; Carleer, M.; Colin, R.; Mérienne, M.-F.; Jenouvrier, A.; Coquart, B. J. Geophys. Res. 2002, 107 (D18), 4348) temperature-corrected cross sections, and (2) the mean pressure-broadened half-width of NO(2) by NO in the 3.4-mum band was measured as being 0.096 +/- 0.001 cm(-1) atm(-1). The latter finding is thought to be unreported by the literature.     

Laboratory intercomparison of the ozone absorption coefficients in the mid-infrared (10 microm) and ultraviolet (300-350 nm) spectral regions

For the measurement of atmospheric ozone concentrations, the mid-infrared and ultraviolet regions are both used by ground-, air-, or satellite-borne instruments. In this study we report the first laboratory intercomparison of the ozone absorption coefficients using simultaneous measurements in these spectral regions. The intercomparison shows good agreement (around 98.5%) between the HITRAN 2000 recommendation for the mid-infrared and the most reference measurements in the ultraviolet regions, whereas systematic differences of about 5.5% are observed when using the recommendation of HITRAN2003 for the mid-infrared. Possible reasons for this discrepancy are discussed. Future measurements are clearly needed to resolve this issue.     

Action spectra for modification of Escherichia coli B/r menaquinone by near-ultraviolet and visible radiations (313-578 nm)

–Menaquinone-8 (MQ-8) was irradiated in vivo in Escherichia coli B/r and in vitro after extraction from E. coli B/r, using monochromatic radiation in the range 313–578 nm. Within experimental error, the action spectra for loss of chromatographic mobility after irradiation in vivo and in vitro agree with each other and with the absorption spectrum of pure MQ-8. The MQ-8 is extremely sensitive to near-UV light (300–380 nm), showing an F₃₇in vivo at 334 nm of 1.3 kj/m², a value 15 times lower than that required for growth delay, and 150 times lower than that for killing, of E. coli B/r. The quantum yield for this reaction in vivo at 334 nm has the very high value of 0.26. The high sensitivity of MQ-8 suggests involvement in near-UV-induced effects on the plasma membrane.     

Electronic spectra of iron monohydride in the infrared near 1.35 and 1.58 microm

The complex, many-line spectrum of FeH, lying in the infrared region between 5500 and 7500 cm(-1), has been shown to consist of two separate electronic transitions: E (4)Pi-X (4)Delta and E (4)Pi-A (4)Pi. High resolution Fourier transform spectra from thermal emission have been rotationally analyzed in detail. Lambda doubling in both the E (4)Pi and A (4)Pi states is considerable. The experimentally determined energies and bond lengths of the newly characterized states are in good agreement with theoretical predictions.     

Non-coherent visible and infrared radiation increase survival to UV (254 nm) in Escherichia coli K12

Interactions between visible or infrared (IR) and ultraviolet (UV, 254 nm) radiation have been studied in E. coli. Pre-illumination with non-coherent monochromatic 446, 466, 570 and 685 nm radiation, as well as with polychromatic red and IR radiation at room temperature, leads to increased cell survival after a subsequent irradiation with UV light. In the thermic range of the spectrum (red and IR), IR but not red light pre-treatment is able to increase cell survival to a subsequent lethal heat (51 degrees C) challenge, suggesting that increased UV survival may be due to IR-induced heat-shock response. On the other hand, visible-light-induced resistance may be due to a different mechanism, possibly involved with unknown bacterial light receptors.     

He (I) and He (II) photoelectron spectra of ozone

The he I (21.2 eV) and He II (40.8 eV) photoelectron spectra of ozone have been recorded under high resolution. Ionization potentials are identified at 12.75 eV, 13.02 eV, 13.57 eV, and two broad bands are centered at 17.7 eV and 20.1 eV. The experimental results and the orbital assignment are not completely in accord with those given recently in the literature.     

Theoretical insights into the visible near‐infrared absorption spectra of Bis(hexafluoroacetylacetonate) copper(II) in pyridine

The density functional theory calculations were performed to investigate the specific solvent effects on the optical absorption spectrum of copper(II) hexafluoroacetylacetonate complex in pyridine. The effects of single and double coordination of pyridine molecules at axial position of bis(hexafluoroacetylacetonate) copper(II) indicate that both positions and intensities of 3d–3d electronic transitions are strongly dependent on the coordination environment around the copper(II) complex. The results indicate that the nature of the electron‐acceptor atoms in the equatorial ligands plays an important role in the number of solvent molecules in the first solvation shell of copper(II) acac systems. © 2011 Wiley Periodicals, Inc. Int J Quantum Chem, 2011     

Electrochemical reduction of 4-(nitrophenyl)-1,2- and 4-(nitrophenyl)-1,4-dihydropyridines and the ESR spectra of the obtained free-radical particles

In the course of electrochemical generation the intermediate reaction products (free radicals of the nitro-and nitrosophenyl type, which appear on the cyclic voltammetric curves) were identified by ESR. The N-substituted derivatives are characterized by reduction of the dihydropyridine ring. The 4-nitrophenyl derivatives are characterized by the absence of intramolecular electron transfer during electrochemical reduction. In the case of the corresponding derivatives of 1,2-dihydropyridine intramolecular transfer of electrons and protons is possible under these conditions. Combined schemes of the primary and secondary chemical reactions involved in the electrochemical reduction of the investigated compounds are presented. It was established that the substances investigated with reference to the mechanism of the electrochemical transformations include the antihypertensive nifedipine (corinfar, fenigidine).Latvian Institute of Organic Synthesis, Riga LV-1006. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 2, pp. 219–233, February, 1997.     

Differences between infrared spectra of atrazine obtained under transmittance and diffuse reflectance modes

We hypothesized that the surface amino-group of chloro-atrazine particles protonates when exposed to atmospheric moisture and therefore an outer layer of chloro-atrazine colloids was expected to transform to hydroxy-atrazine. To test the hypothesis we compared transmittance infrared (FT-IR) spectra with diffuse reflectance spectra of pure chloro- and hydroxy-atrazine under various treatments and two commercial forms of atrazine, AATREX-4L and AATREX-90. These spectral comparisons indicated that a certain number of chloro-atrazine molecules in the outer-layer of chloro-atrazine crystals transformed to protonated hydroxy-atrazine molecules. This is believed to have practical implications on the fate and mobility of atrazine in the field.     

Study of infrared and mass spectra of N-2-(3'-phthalide-yl)phthalazin-1-one

The infrared and mass spectra of N-2-(3'-phthalide-yl)phthalazin-1-one were studied. The loss of one or two natural CO residues was observed from the title compound and its partial fragment ions. Using the MIKE spectrum of ion m/z 250, its most possible structure was confirmed. Two possible paths of the formation of the title compound were also proposed.     

CCSD(T) study of dimethyl-ether infrared and Raman spectra

CCSD(T) state-of-the-art ab initio calculations are used to determine a vibrationally corrected three-dimensional potential energy surface of dimethyl-ether depending on the two methyl torsions and the COC bending angle. The surface is employed to obtain variationally the lowest vibrational energies that can be populated at very low temperatures. The interactions between the bending and the torsional coordinates are responsible for the displacements of the torsional overtone bands and several combination bands. The effect of these interactions on the potential parameters is analyzed. Second order perturbation theory is used as a help for the understanding of many spectroscopic parameters and to obtain anharmonic fundamentals for the 3N - 9 neglected modes as well as the rotational parameters. To evaluate the surface accuracy and to verify previous assignments, the calculated vibrational levels are compared with experimental data corresponding to the most abundant isotopologue. The surface has been empirically adjusted for understanding the origin of small divergences between ab initio calculations and experimental data. Our calculations confirm previous assignments and show the importance of including the COC bending degree of freedom for computing with a higher accuracy the excited torsional term values through the Fermi interaction. Besides, this work shows a possible lack of accuracy of some available experimental transition frequencies and proposes a new assignment for a transition line. As an example, the transition 100 → 120 has been computed at 445.93 cm(-1), which is consistent with the observed transition frequency in the Raman spectrum at 450.5 cm(-1).     

Fourier transform infrared and Raman spectra of N-di-isopropylphosphorylguanidine (DPG)

The Fourier transform infrared and the Fourier transform Raman spectra of N-di-isopropylphosphorylguanidine (DPG) in the solid state and in aqueous solution were recorded and analyzed. Assuming Cs symmetry for different structural fragment of the molecule, the experimental and calculated band assignments of the nu(NH), delta(HNH), delta(CNH), nu(C=N), nu(PN), nu(CN), nu(PO) and nu(OC) normal modes suggested that the DPG exists as a tautomeric contribution of the phosphorylamine (I) and N-phosphorylimine (II) structural forms. [structures: see text]     

Genotoxicity of visible light (400-800 nm) and photoprotection assessment of ectoin, L-ergothioneine and mannitol and four sunscreens

This study was designed to determine the genotoxic effects of visible (400-800nm) and ultraviolet A (UVA)/visible (315-800nm) lights on human keratinocytes and CHO cells. The alkaline comet assay was used to quantify DNA-damage. In addition, photo-dependent cytogenetic lesions were assessed in CHO cells by the micronucleus test. Three protective compounds [ectoin, l-ergothioneine (ERT) and mannitol] were tested with the comet assay for their effectiveness to reduce DNA single-strand breaks (SSB). Finally, the genomic photoprotections of two broad-band sunscreens and their tinted analogues were assessed by the comet assay. The WST-1 cytotoxicity assay revealed a decrease of the keratinocyte viability of 30% and 13% for the highest UVA/visible and visible irradiations (15 and 13.8J/cm(2), respectively). Visible as well as UVA/visible lights induced DNA SSB and micronuclei, in a dose-dependent manner. The level of DNA breakage induced by visible light was 50% of the one generated by UVA/visible irradiation. However, UVA radiations were 10 times more effective than visible radiations to produce SSB. The DNA lesions induced by visible and UVA/visible lights were reduced after a 1-h preincubation period with the three tested compounds. The maximal protective effects were 92.7%, 97.9% and 52.0% for ectoin (0.1mM), ERT (0.5mM) and mannitol (1.5mM), respectively, against visible light and 68.9%, 59.8% and 62.7% for ectoin (0.1mM), ERT (0.5mM) and mannitol (1.5mM), respectively, against UVA/visible light. Thus, visible light was genotoxic on human keratinocytes and CHO cells through oxidative stress mechanisms similar to the ones induced by UVA radiations. The four tested sunscreens efficiently prevented DNA lesions that were induced by both visible and UVA/visible irradiations. The tinted sunscreens were slightly more effective that their colorless analogues. There is a need to complement sunscreen formulations with additional molecules to obtain a complete internal and external photoprotection against both UVA and visible lights.     

Near infrared spectra (4000-10 500 cm-1) of phenol-OH and phenol-OD in carbon tetrachloride

The near infrared spectra (3800-10 500 cm(-1) of phenol-OH and phenol-OD are studied in carbon tetrachloride solution. The bandwidth of the v(OH) and v(OD) stretching vibrations increases with the vibrational quantum number in contrast to results obtained by nonresonant ionization spectroscopy (S.I. Ishiuchi et al., Chem. Phys. Lett. 283 (1998) 243). The bandwidth of the v(CH) vibrations obtained by a deconvolution procedure also increases with the frequencies associated with the vibrational transitions. The anharmonicity of the v(CH) vibrations ranges between 51 and 72 cm(-1). Numerous absorptions are observed in the near infrared spectra. These absorptions are tentatively assigned to combinations involving the fundamental transitions which have been recently calculated at different levels of theory (D. Michalska et al., J. Phys. Chem. 100 (1996) 17786). The experimental, theoretical and harmonic v(OH) and vi(CH) frequencies are compared.     

Synthesis, Fourier transform infrared and Raman spectra, assignments and analysis of N-(phenyl)- and N-(chloro substituted phenyl)-2,2-dichloroacetamides

N-(phenyl)-2,2-dichloroacetamide (NPA) and N-(chloro substituted phenyl)-2,2-dichloroacetamides of the configuration XyC6H(5-y)-NHCO-CHCl2 (where, X = Cl and y = 1, 2 and 3) were synthesised and the Fourier transform infrared (FTIR) and Fourier transform Raman (FT-Raman) spectra of the compounds were recorded and analysed. The FTIR spectra of all the compounds were recorded in a Bruker IFS 66V spectrometer in the range of 4000-400 cm(-1) and the FT-Raman spectra were also recorded in the same instrument in the region 3500-100 cm(-1). The variation of an amide bond (-NHCO-) parameters with the substitution of the chlorine atom in the phenyl group and the mixing of different normal modes are discussed with the help of potential energy distribution (PED) calculated through normal co-ordinate analysis.     

Simulated infrared spectra of Ho(III) and Gd(III) chlorides and carboxylate complexes using effective core potentials in GAMESS.

The mid- and far-infrared spectra of Ho(III) and Gd(III) chloride hexahydrate, anhydrous Gd(III) formate, Ho(III) and Gd(III) acetate hemihydrate and trihydrate, and Gd(III) benzoate monohydrate have been computed by the ROHF/SBKJC method in GAMESS. The calculated spectra successfully simulated the experimental spectra down to 50 cm(-1). Absorptions due to coordinated water were distinguished from those due to O-C-O bending in chelate rings. The number of water molecules bound to Ln(III) in a complex was successfully predicted from the match of the experimental spectra to the simulated Ln-O vibrations in the far IR.     

Structures and infrared spectra of fluoride-hydrogen sulfide clusters from ab initio calculations: F(-)-(H2S)n, n = 1-5

Clusters formed between a fluoride anion and several hydrogen sulfide molecules have been investigated via ab initio calculations at the MP2 level of theory, using Dunning's augmented correlation consistent basis sets. Optimised geometries, vibrational frequencies, and enthalpy changes for the ligand association reactions are presented for clusters with up to five H2S ligands interacting with a F- anion. The minimum energy structure for the 1:1 F(-)-H2S complex features proton transfer from the H2S to the F- anion, forming a planar C(s) symmetry FH...SH- structure. For the F(-)-(H2S)2 cluster, the FH...SH- core remains and is solvated by a perturbed H2S ligand. For the larger F(-)-(H2S)(3-5) clusters, in addition to the FH...SH(-)-(H2S)n cluster forms, other minima featuring a 'solvated F-' anion are predicted. Calculated infrared spectra for the minima of each cluster size are presented to aid in assigning spectra from future experimental studies.     

应用超声波电化学法同时测定Pb、Cu

研究了超声波对Pb(Ⅱ）、Cu（Ⅱ）同时电分析化学测定条件的影响，并对其作用机理进行了初探。利用超声波的空化作用加快了质量传递，提高了电极活性，在电极表面即产生机械效应又产生热效应，从而提高了Pb、Cu同时电化学测定的灵敏度。     

The infrared spectra of gaseous 1,1,3,3-tetrachlorotetrafluoro-4-(trifluoromethyldioxy)butyl trifluoromethyl ether and 1,1,3,3-tetrachlorotetrafluoro-1,4-bis(trifluoromethoxy)butane

1,1,3,3-Tetrachlorotetrafluoro-4-(trifluoromethyldioxy)butyl trifluoromethyl ether, CF₃O(CF₂CCl₂)₂O₂CF₃, was formed as one of the products in the reaction of CF₃O₃CF₃ with CF₂CCl₂ at 322.6 - 342.5 K. It was isolated by fractional condensation between 213 and 243 K and characterized by molecular weight determination and ¹⁹F NMR spectrum. 1,1,3,3-Tetrachlorotetrafluoro-1,4-bis(trifluoromethoxy)butane, CF₃O(CF₂CCl₂)₂OCF₃, was condensed as residue at 193 K from the reaction of CF₃OF with CF₂CCl₂ at 266 - 302.7 K, when [CF₂CCl₂]/[CF₃OF] ≦ 0.5. It was characterized by gas chromatography and molecular weight determination. The infrared spectra of both compounds are given, providing additional support for their characterization.     

Comparison of the erythemogenic effectiveness of ultraviolet-B (290-320 nm) and ultraviolet-A (320-400 nm) radiation by skin reflectance

–Based on optical properties of the skin, its constituent layers and the blood, and a previously experimentally verified quantitative model for the optical transfer properties in skin, noninvasive determinations of the amount of cutaneous blood in the superficial plexus are made from skin reflectance. This method is used to determine UVA and UVB fluences that cause cutaneous blood in the superficial plexus to increase to 1.5, 2 and 2.5 times the pre-radiation volume at various times after irradiation. Our results show that on an equal fluence basis, UVB is two to three thousand times as effective as UVA in inducing erythema, whether erythema is evaluated 8, 24 or 72 h after irradiation. This agrees with the result obtained in terms of minimal erythema dose by visual inspection.