169 results match your criteria vuv spectral


UV/Vis photochemistry database: Structure, content and applications.

J Quant Spectrosc Radiat Transf 2020 Sep;253

Chemistry Department, University of Oxford, South Parks Road, Oxford, OX1 3QR, United Kingdom.

The "science-softCon UV/Vis Photochemistry Database" (www.photochemistry.org) is a large and comprehensive collection of EUV-VUV-UV-Vis-NIR spectral data and other photochemical information assembled from published peer-reviewed papers. Read More

View Article and Full-Text PDF
September 2020

Improvement of quantum efficiency through Gd to Eu energy transfer in YF phosphor.

Luminescence 2021 Apr 30. Epub 2021 Apr 30.

Department of Physics, Sant Gadge Baba Amravati University, Amravati, India.

This paper reports the energy transfer from Gd to Eu in YF and the consequent downconversion luminescence for the YF :Gd , Eu fluoride phosphor. The phosphor was synthesized using a soft chemical route, followed by a reactive atmosphere process. Because of the wide band gap in YF and the correct energy site for S - G transitions of Gd ions, fluoride YF doped with Gd -Eu were studied in their vacuum-ultraviolet (VUV) spectral regions. Read More

View Article and Full-Text PDF

Proton Transfer in Nitromethane-Ammonia Clusters under VUV Single-Photon Ionization Explored by Infrared Spectroscopy and Theoretical Calculations.

J Phys Chem A 2021 Apr 20;125(16):3279-3287. Epub 2021 Apr 20.

MOE Key Laboratory of Laser Life Science & Guangdong Provincial Key Laboratory of Laser Life Science, Guangzhou Key Laboratory of Spectral Analysis and Functional Probes, College of Biophotonics, South China Normal University, Guangzhou 510631, China.

It is known that the acidity and reactivity of the CH bond can be enhanced after ionization. Also, this property plays a pivotal role in proton transfer reaction and in the formation of new molecules. Herein, infrared spectroscopy and high-precision quantum chemical calculations are used to study the neutral and cationic clusters of nitromethane-ammonia (CHNO-NH). Read More

View Article and Full-Text PDF

Spotting isomer mixtures in forensic illicit drug casework with GC-VUV using automated coelution detection and spectral deconvolution.

J Chromatogr B Analyt Technol Biomed Life Sci 2021 Mar 29;1173:122675. Epub 2021 Mar 29.

Van 't Hoff Institute for Molecular Sciences, University of Amsterdam, PO Box 94157, Amsterdam 1090 GD, the Netherlands; Co van Ledden Hulsebosch Center (CLHC), Amsterdam Center for Forensic Science and Medicine, PO Box 94157, Amsterdam 1090 GD, the Netherlands.

Analysis of isomeric mixtures is a significant analytical challenge. In the forensic field, for example, over 1000 new psychoactive substances (NPSs), comprising of many closely related and often isomeric varieties, entered the drugs-of-abuse market within the last decade. Unambiguous identification of the isomeric form requires advanced spectroscopic techniques, such as GC-Vacuum Ultraviolet Spectroscopy (GC-VUV). Read More

View Article and Full-Text PDF

Spectroscopic evidence of the C-N covalent bond formed between two interstellar molecules (ISM): acrylonitrile and ammonia.

Phys Chem Chem Phys 2021 Apr;23(16):9672-9678

MOE Key Laboratory of Laser Life Science & Guangdong Provincial Key Laboratory of Laser Life Science, Guangzhou Key Laboratory of Spectral Analysis and Functional Probes, College of Biophotonics, South China Normal University, Guangzhou 510631, China.

Acrylonitrile (AN) and ammonia (NH3) are two important nitrogen-containing interstellar molecules in outer space, especially on Titan. Herein, we measured infrared (IR) spectra of neutral and cationic AN-NH3 complexes by VUV single-photon ionization combined with time-of-flight mass spectrometry. On combining IR spectra with the theoretical calculations, we found that the molecules prefer to form a single-ring cyclic H-bonded structure in the neutral AN-NH3 and (AN)2-NH3 clusters. Read More

View Article and Full-Text PDF

Sulfur Detection in Soil by Laser Induced Breakdown Spectroscopy Assisted by Multivariate Analysis.

Materials (Basel) 2021 Jan 23;14(3). Epub 2021 Jan 23.

Department of Physics, University of Patras, 26504 Patras, Greece.

Laser-induced breakdown spectroscopy (LIBS) is used for the detection and determination of sulfur content in some organic soil samples. The most suitable sulfur spectral lines for such tasks were found to occur in the vacuum ultraviolet (VUV) spectral region and they were used for the construction of calibration curves. For the analysis, both univariate and multivariate statistical models were employed. Read More

View Article and Full-Text PDF
January 2021

Method development and evaluation of pyrolysis oils from mixed waste plastic by GC-VUV.

J Chromatogr A 2021 Jan 23;1637:461837. Epub 2020 Dec 23.

Dow Benelux BV, Herbert H. Dowweg 5, 4542 NM, Hoek, the Netherlands.

The conversion of waste streams into a useable material through a recycling process is a hot topic. Waste streams can originate from domestic and industrial sources and range from plastic waste to medical waste to various industrial waste streams, both solid and liquid. In addition to waste circularity, circularity for bio-based waste streams and renewable sources are also being investigated. Read More

View Article and Full-Text PDF
January 2021

Laser-Induced Chemistry Observed during 248 nm Vacuum Ultraviolet Photolysis of an O and CHNH Mixture.

J Phys Chem A 2020 Dec 14;124(51):10838-10848. Epub 2020 Dec 14.

Department of Chemistry, Emory University, Atlanta, Georgia 30322-1007, United States.

We present an examination of the 248 nm VUV (vacuum ultraviolet) laser photolysis of an ozone (O) and methylamine (CHNH) mixture as means to produce aminomethanol (NHCHOH). Aminomethanol is predicted to be the direct interstellar precursor to glycine and is therefore an important target for detection in the interstellar medium. However, due to its high reactivity under terrestrial conditions, aminomethanol evades gas-phase spectral detection. Read More

View Article and Full-Text PDF
December 2020

Time-resolved luminescence and excitation spectroscopy of Co-doped GdGaAlO scintillating crystals.

Sci Rep 2020 Nov 23;10(1):20388. Epub 2020 Nov 23.

Institute of Solid State Physics, University of Latvia, 8 Kengaraga iela, Riga, LV-1063, Latvia.

Cerium doped GdGaAlO (GGAG) single crystals as well as GGAG:Ce single crystals co-doped by divalent (Mg, Ca) and tetravalent (Zr, Ti) ions have been studied by means of time-resolved luminescence as well as the excitation luminescence spectroscopy in vacuum ultraviolet (VUV) and soft X-ray (XUV) spectral range. Tunable laser excitation was applied for time-resolved experiments in order to obtain luminescence decay curves under excitations in Ce, Gd and excitonic absorption bands. The influence of the co-dopant ions on the Ce luminescence decay kinetics is elucidated. Read More

View Article and Full-Text PDF
November 2020

Photoluminescence of diamond containing nitrogen vacancy defects as a sensor of temperature upon exposure to vacuum- and extreme-ultraviolet radiation.

Phys Chem Chem Phys 2020 Dec;22(46):26982-26986

National Synchrotron Radiation Research Center, 101 Hsin-Ann Road, Hsinchu Science Park, Hsinchu 300, Taiwan.

Upon excitation with vacuum-ultraviolet (VUV) and extreme-ultraviolet (EUV) radiation, diamond with nitrogen vacancies (DNV) emits strong photoluminescence (PL) in the wavelength region of 550-800 nm. The spectral profiles of the DNV in the PL spectra appear to be strongly dependent on the temperature of the diamond. Moreover, all PL spectra intersect at one isosbestic point, 570 nm; this result is evidence that the NV0 and NV- defects in diamond interconvert with each other upon VUV and EUV radiation. Read More

View Article and Full-Text PDF
December 2020

Vibrationally resolved valence and core photoionization and photoexcitation spectra of an electron-deficient trivalent boron compound: the case of catecholborane.

Phys Chem Chem Phys 2020 Nov 3;22(43):25396-25407. Epub 2020 Nov 3.

Department of Physical Chemistry, Ruđer Bošković Institute, Bijenička cesta 54, HR-10000, Zagreb, Croatia.

Compounds containing trivalent boron (TB) as the electron-deficient site(s) find numerous practical uses ranging from Lewis bases in organic synthesis to high-tech industry, with a number of novel applications anticipated. We present an experimental and theoretical study of the gas-phase valence photoionization (VUV-PES), core photoionization (XPS) and photoexcitation (NEXAFS) spectra of a representative TB compound catecholborane (CB). For modelling and assigning the spectra we used the ΔDFT and restricted single excitation space TD-DFT methods for the XPS and NEXAFS, and OVGF and EOM-CCSD for the VUV-PES. Read More

View Article and Full-Text PDF
November 2020

Correlation-based carbon determination in steel without explicitly involving carbon-related emission lines in a LIBS spectrum.

Opt Express 2020 Oct;28(21):32019-32032

As any spectrochemical analysis method, laser-induced breakdown spectroscopy (LIBS) usually relates characteristic spectral lines of the elements or molecules to be analyzed to their concentrations in a material. It is however not always possible for a given application scenario, to rely on such lines because of various practical limitations as well as physical perturbations in the spectrum excitation and recording process. This is actually the case for determination of carbon in steel with LIBS operated in the ambient gas, where the intense C I 193. Read More

View Article and Full-Text PDF
October 2020

Photoluminescence of optical windows excited with extreme ultraviolet radiation.

Opt Lett 2020 Oct;45(19):5413-5415

Upon excitation with extreme ultraviolet (EUV) radiation, optical windows and sapphire emit strong photoluminescence (PL) in the ultraviolet region 200-400 nm. The spectral profiles of the windows observed in the PL spectra appear strongly dependent on their temperature. We suggest the use of PL spectra of and sapphire excited with EUV light to indicate the temperature for EUV applications such as nano-photolithography technology in manufacturing semiconductor devices; potentially, the method is applicable to a wide range of radiation including the vacuum-ultraviolet (VUV) and EUV regions and in all fields. Read More

View Article and Full-Text PDF
October 2020

Determination of the highest occupied molecular orbital and cationic structure of 2-chloropyridine by one-photon VUV-MATI spectroscopy and Franck-Condon fitting.

Phys Chem Chem Phys 2020 Sep;22(36):20858-20866

Department of Chemistry and Institute for Molecular Science and Fusion Technology, Kangwon National University, Chuncheon 24341, Korea.

2-Chloropyridine (2-CP) has received significant attention, owing to the effect of the substitution of a halogen in pyridine on the highest occupied molecular orbital (HOMO). To elucidate the substitution effect of the chlorine atom on the HOMO of pyridine, we obtained one-photon vacuum ultraviolet mass-analysed threshold ionization (VUV-MATI) spectra of 2-CP having 35Cl or 37Cl to analyse the isotope effect on the vibrational mode. Based on the 0-0 band in the MATI spectrum of 2-CP having 35Cl, the adiabatic ionization energy was determined to be 9. Read More

View Article and Full-Text PDF
September 2020

Quantum efficiency of black silicon photodiodes at VUV wavelengths.

Opt Express 2020 Apr;28(9):13299-13309

Black silicon (b-Si) is an emerging material made by modifying silicon with nanostructures for improved photon detection. It has been demonstrated that when used in photodetectors b-Si significantly improves photon detection and extends spectral sensitivity from NIR to the visible wavelengths. However, no data have been reported in the Vacuum Ultraviolet (VUV) range, which is increasingly becoming important for many applications. Read More

View Article and Full-Text PDF

A synchronized VUV light source based on high-order harmonic generation at FLASH.

Sci Rep 2020 Apr 22;10(1):6867. Epub 2020 Apr 22.

Institut für Quantenoptik, Leibniz Universität Hannover, Hannover, 30167, Germany.

Ultrafast measurements in the extreme ultraviolet (XUV) spectral region targeting femtosecond timescales rely until today on two complementary XUV laser sources: free electron lasers (FELs) and high-harmonic generation (HHG) based sources. The combination of these two source types was until recently not realized. The complementary properties of both sources including broad bandwidth, high pulse energy, narrowband tunability and femtosecond timing, open new opportunities for two-color pump-probe studies. Read More

View Article and Full-Text PDF

Short-wavelength probes in time-resolved photoelectron spectroscopy: an extended view of the excited state dynamics in acetylacetone.

Phys Chem Chem Phys 2020 Feb;22(8):4647-4658

Institute of Photonics & Quantum Sciences, Heriot-Watt University, Edinburgh, EH14 4AS, UK. and Institute of Chemical Sciences, Heriot-Watt University, Edinburgh, EH14 4AS, UK.

Femtosecond pulses of light in the vacuum ultraviolet (VUV) spectral region permit extended observation of non-adiabatic dynamics in gas-phase molecules. When used as a probe in time-resolved photoelectron spectroscopy, such pulses project deeply into the ionization continuum and allow the evolution of excited state population to be monitored across multiple potential energy surfaces. When compared with longer-wavelength probes, this often provides a more complete view along the reaction coordinate(s) connecting photoreactants to photoproducts. Read More

View Article and Full-Text PDF
February 2020

Kinetic selection of nonradiative excitation in photonic nanoparticles GdO:Er.

Phys Chem Chem Phys 2020 Apr 29;22(13):6818-6825. Epub 2020 Jan 29.

Photonics and VUV-spectroscopy Lab, Institute of Physics and Technology, Ural Federal University, Ekaterinburg, Russia.

In the present work, we separate and classify four different pathways for UV-vis energy conversion with participation of Gd and Er ions located at dissimilar structural sites in the GdO lattice. The Gd centers represent host cations with a distorted environment due to the nearest defects of the anionic sublattice. Two non-equivalent types of both Gd donor and Er acceptor centers occupying C and S structural sites are selected in GdO:Er nanoparticles by the spectral-kinetic method. Read More

View Article and Full-Text PDF

Infrared Spectroscopy of Hydrogen-Bonding Interactions in Neutral Dimethylamine-Methanol Complexes.

J Phys Chem A 2019 Nov 7;123(46):10109-10115. Epub 2019 Nov 7.

State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics , Chinese Academy of Sciences , 457 Zhongshan Road , Dalian 116023 , China.

Infrared spectra of the neutral dimethylamine-methanol cluster, DMA-CHOH, were measured in the spectral range of 2800-3900 cm using an infrared-vacuum ultraviolet (IR-VUV) scheme. Quantum chemical calculations and ab initio molecular dynamic (AIMD) simulations were carried out to understand the experimental spectral features. Experimental and theoretical results reveal the coexistence of N···HO and O···HN hydrogen-bonded structures. Read More

View Article and Full-Text PDF
November 2019

Structural rearrangement of the acrylonitrile (AN) cluster in the gas phase under VUV one-photon radiation explored by mass-selected infrared spectroscopy.

Spectrochim Acta A Mol Biomol Spectrosc 2020 Feb 7;226:117620. Epub 2019 Oct 7.

MOE Key Laboratory of Laser Life Science & Institute of Laser Life Science, College of Biophotonics, Guangzhou Key Laboratory of Spectral Analysis and Functional Probes, South China Normal University, Guangzhou, 510631, PR China. Electronic address:

Acrylonitrile (AN), one of the most abundant nitriles in space, is considered to closely relate to the formation of interstellar prebiotic nitrogen-containing aromatics. Herein, we measured the vibrational spectra of acrylonitrile cluster cations (AN) in a supersonic jet using infrared (IR) dissociation with vacuum-ultraviolet (VUV) photoionization and time-of-flight mass spectroscopy. Interestingly, the observed IR spectra demonstrate that a new molecular ion [Formula: see text] , is generated from the dimer and trimer of AN upon VUV single-photo ionization. Read More

View Article and Full-Text PDF
February 2020

Simulation of Vacuum Ultraviolet Absorption Spectra: Paraffin, Isoparaffin, Olefin, Naphthene, and Aromatic Hydrocarbon Class Compounds.

Appl Spectrosc 2020 Jan 13;74(1):72-80. Epub 2019 Sep 13.

Department of Chemistry and Biochemistry, The University of Texas at Arlington, Arlington, USA.

The advent of a new vacuum ultraviolet (VUV) spectroscopic absorption detector for gas chromatography has enabled applications in many areas. Theoretical simulations of VUV spectra using computational chemistry can aid the new technique in situations where experimental spectra are unavailable. In this study, VUV spectral simulations of paraffin, isoparaffin, olefin, naphthene, and aromatic (PIONA) compounds using time-dependent density functional theory (TDDFT) methods were investigated. Read More

View Article and Full-Text PDF
January 2020

Distinguishing drug isomers in the forensic laboratory: GC-VUV in addition to GC-MS for orthogonal selectivity and the use of library match scores as a new source of information.

Forensic Sci Int 2019 Sep 26;302:109900. Epub 2019 Jul 26.

Van 't Hoff Institute for Molecular Sciences, University of Amsterdam, Postbus 94157, Amsterdam 1090 GD, Netherlands; Co van Ledden Hulsebosch Center (CLHC), Amsterdam Center for Forensic Science and Medicine, Postbus 94157, Amsterdam 1090 GD, Netherlands.

Currently, forensic drug experts are facing chemical identification challenges with the increasing number of new isomeric forms of psychoactive substances occurring in case samples. Very similar mass spectra for these substances could easily result in misidentification using the regular GC-MS screening methods in combination with colorimetric testing in forensic laboratories. Building on recent work from other groups, this study demonstrates that GC-VUV is a powerful technique for drug isomer differentiation, showing reproducible and discriminating spectra for aromatic ring-isomers. Read More

View Article and Full-Text PDF
September 2019

Formation of HCO and HCS Ions in the Photodissociation of CHOC(S)SCH under VUV Synchrotron Radiation.

J Phys Chem A 2019 Aug 30;123(31):6674-6682. Epub 2019 Jul 30.

CEQUINOR (UNLP-CONICET, CCT La Plata, associated with CIC PBA). Departamento de Química, Facultad de Ciencias Exactas , Universidad Nacional de la Plata . Boulevard 120 e/ 60 y 64 No 1465 CP 1900 , La Plata , República Argentina.

Synchrotron-based total ion yield and photoelectron-photoion-coincidence spectra have been applied to investigate the electronic structure and the dissociative ionization of gaseous ,-dimethyl xanthate, CHOC(S)SCH, in the shallow-core S 2p region. The spectral assignment and the electronic structure are interpreted in terms of the most stable synperiplanar conformer in the symmetry point group. The use of tunable synchrotron radiation allows for a selective excitation of sulfur atoms at different photon energy values, including resonance transitions and ionization around the S 2p level. Read More

View Article and Full-Text PDF

An X-ray gas monitor for free-electron lasers.

J Synchrotron Radiat 2019 Jul 12;26(Pt 4):1092-1100. Epub 2019 Jun 12.

Deutsches Elektronen-Synchrotron (DESY), Notkestrasse 85, D-22607 Hamburg, Germany.

A novel X-ray gas monitor (XGM) has been developed which allows the measurement of absolute photon pulse energy and photon beam position at all existing and upcoming free-electron lasers (FELs) over a broad spectral range covering vacuum ultraviolet (VUV), extreme ultraviolet (EUV) and soft and hard X-rays. The XGM covers a wide dynamic range from spontaneous undulator radiation to FEL radiation and provides a temporal resolution of better than 200 ns. The XGM consists of two X-ray gas-monitor detectors (XGMDs) and two huge-aperture open electron multipliers (HAMPs). Read More

View Article and Full-Text PDF

Formyl torsion and cationic structure of gauche conformer in isobutanal by conformer-specific VUV-MATI spectroscopy and Franck-Condon fitting.

J Chem Phys 2019 Jul;151(1):014304

Department of Chemistry and Institute for Molecular Science and Fusion Technology, Kangwon National University, Chuncheon 24341, South Korea.

We report conformational and vibrational assignments of vacuum ultraviolet mass-analyzed threshold ionization spectrum of the isolated gauche conformer, based on previously determined conformer-specific photoionization and conformational stabilities of isobutanal. The vibrational spectrum of the pure cationic gauche conformer was acquired by removing the trans conformer via conformationally effective cooling with Ar carrier gas. The peaks in the spectrum were assigned by Franck-Condon (FC) fitting by adjusting the cationic geometrical parameters of the gauche conformer at the CAM-B3LYP/cc-pVTZ level. Read More

View Article and Full-Text PDF

Vibronic structure of the cyanobutadiyne cation. I. VUV photoionization study of HCN.

J Chem Phys 2019 Jun;150(24):244304

Institut des Sciences Moléculaires d'Orsay (ISMO), CNRS UMR 8214, Univ. Paris-Sud, Université Paris-Saclay, F-91405 Orsay, France.

We report the vacuum-ultraviolet threshold-photoelectron spectrum of HCN recorded over a wide spectral range, from 84 000 to 120 000 cm, with a 120 cm spectral resolution, better than what was achieved in previous photoelectron studies, and with mass selectivity. The adiabatic ionization potential of cyanobutadiyne is measured at 85 366 (±40) cm. Assignment of the vibrational bands of the four lowest electronic states XΠ, AΠ, BΣ, and CΠ are performed, supported by high level ab initio calculations which are fully detailed in Paper II [B. Read More

View Article and Full-Text PDF

Evaluation and application of gas chromatography - vacuum ultraviolet spectroscopy for drug- and explosive precursors and examination of non-negative matrix factorization for deconvolution.

Spectrochim Acta A Mol Biomol Spectrosc 2019 Aug 17;219:129-134. Epub 2019 Apr 17.

Joint Mass Spectrometry Centre, Chair of Analytical Chemistry, University of Rostock, Dr.-Lorenz-Weg 2, 18059 Rostock, Germany; Joint Mass Spectrometry Centre, Comprehensive Molecular Analytics, Helmholtz Zentrum München, Ingolstädter Landstr. 1, 85764 Neuherberg, Germany.

Since the introduction of a benchtop vacuum ultraviolet (VUV) absorption spectroscope with an increased wavelength range towards to the high energetic ultraviolet radiation, gas chromatography coupled to VUV has been proven a powerful tool in several fields of application such as petroleomics, permanent gas analytic, pesticide analytic and many more. In this study, the potential of GC-VUV for investigations was examined, focusing on drug- and explosive precursors as well as chemical warfare simulants. The ability of VUV absorption spectra to differentiate isomers is presented, among others for nitroaromatics. Read More

View Article and Full-Text PDF

Conformational preference and cationic structure of 2-methylpyrazine by VUV-MATI spectroscopy and natural bond orbital analysis.

Phys Chem Chem Phys 2019 May;21(18):9255-9264

Department of Chemistry, College of Natural Sciences and Institute for Molecular Science and Fusion Technology, Kangwon National University, Chuncheon 24341, Korea.

Alkylpyrazines, which are well-known as aromatic substances and traditional medicines, are interesting molecular systems, and their methyl conformations result in unique structural and dynamical properties. We explored the conformational preference of the methyl group and the highest occupied molecular orbitals (HOMOs) of 2-methylpyrazine and its cation by utilizing high-resolution one-photon vacuum ultraviolet mass-analyzed threshold ionization (VUV-MATI) spectroscopy and natural bond orbital analysis to understand the relevant molecular activities. The measured VUV-MATI spectrum of 2-methylpyrazine revealed its adiabatic ionization energy and the vibrational frequencies of its cation. Read More

View Article and Full-Text PDF

All-solid-state VUV frequency comb at 160 nm using high-harmonic generation in nonlinear femtosecond enhancement cavity.

Opt Express 2019 Mar;27(5):6618-6628

We realized a solid-state-based vacuum ultraviolet frequency comb by harmonics generation in an external enhancement cavity. Optical conversions were so far reported by only using gaseous media. We present a theory that allows the most suited solid generation medium to be selected for specific target harmonics by adapting the material's bandgap. Read More

View Article and Full-Text PDF

Competition between folded and extended structures of alanylalanine (Ala-Ala) in a molecular beam.

Phys Chem Chem Phys 2019 Jul 14;21(26):14126-14132. Epub 2019 Mar 14.

University of Gothenburg, Department of Physics, 412 96 Gotheburg, Sweden.

We report the gas phase conformational preferences of laser desorbed Ala-Ala dipeptides probed by action spectroscopy using the IRMPD-VUV method. The molecules were internally cooled through collisional cooling in a supersonic jet environment. An IR spectrum was obtained experimentally in the spectral range of 700-1850 cm, and subsequently interpreted with the help of quantum chemical calculations. Read More

View Article and Full-Text PDF