A5012252771- Spectroscopy and Laser Applications
- Advanced Chemical Physics Studies
- Molecular Spectroscopy and Structure
- Atmospheric Ozone and Climate
- Spectroscopy and Quantum Chemical Studies
- X-ray Diffraction in Crystallography
- Mass Spectrometry Techniques and Applications
- Laser Design and Applications
- Crystallization and Solubility Studies
- Crystallography and molecular interactions
- Atmospheric and Environmental Gas Dynamics
- Photosynthetic Processes and Mechanisms
- Advanced Chemical Sensor Technologies
- Photochemistry and Electron Transfer Studies
- Porphyrin and Phthalocyanine Chemistry
- Microbial Metabolic Engineering and Bioproduction
- Spectroscopy Techniques in Biomedical and Chemical Research
- Analytical Chemistry and Sensors
- Advanced NMR Techniques and Applications
- Inorganic Fluorides and Related Compounds
- Heme Oxygenase-1 and Carbon Monoxide
- Neonatal Health and Biochemistry
- Hemoglobin structure and function
- Molecular spectroscopy and chirality
- Photoreceptor and optogenetics research
University of Sheffield
2015-2024
ETH Zurich
1995-2024
University of Münster
2019-2021
Okayama University
2020-2021
Rutherford Appleton Laboratory
2007
European Synchrotron Radiation Facility
2007
University of Strathclyde
2007
Goethe University Frankfurt
2007
Heriot-Watt University
1992-1995
We report on improvements made our previously introduced technique of cavity-enhanced Raman spectroscopy (CERS) with optical feedback cw-diode lasers in the gas phase, including a new mode-matching procedure which keeps laser resonance cavity without inducing long-term frequency shifts laser, and using CCD camera improved noise performance. With 10 mW 636.2 nm diode excitation 30 s integration time, enhancement achieves noise-equivalent detection limits below 1 mbar at bar total pressure,...
Carbon monoxide (CO)-releasing molecules (CORMs), mostly metal carbonyl compounds, are extensively used as experimental tools to deliver CO, a biological 'gasotransmitter', in mammalian systems. CORMs also explored potential novel antimicrobial drugs, effectively and rapidly killing bacteria vitro animal models, but reportedly benign towards cells. Ru-carbonyl CORMs, exemplified by CORM-3 (Ru(CO)3Cl(glycinate)), exhibit the most potent effects against Escherichia coli. We demonstrate that...
A variant of cavity-enhanced Raman spectroscopy (CERS) is introduced, in which diode laser radiation at 635 nm coupled into an external linear optical cavity composed two highly reflective mirrors. Using feedback stabilisation, build-up circulating power by 3 orders magnitude occurs. Strong signals are collected forward scattering geometry. Gas phase CERS spectra H(2), air, CH(4) and benzene recorded to demonstrate the potential for analytical applications fundamental molecular studies....
Hydrogen chloride gas (HCl) is absorbed (and reversibly released) by a nonporous crystalline solid, [CuCl2(3-Clpy)2] (3-Clpy = 3-chloropyridine), under ambient conditions leading to conversion from the blue coordination compound yellow salt (3-ClpyH)2[CuCl4]. These reactions require substantial motions within solid including change in copper environment square planar tetrahedral. This process also involves cleavage of covalent bond gaseous molecules (H−Cl) and bonds molecular (Cu−N)...
We set out to investigate the antibacterial activity of a new Mn-based photoactivated carbon monoxide-releasing molecule (PhotoCORM, [Mn(CO)3(tpa-κ(3)N)](+)) against an antibiotic-resistant uropathogenic strain (EC958) Escherichia coli.Activated PhotoCORM inhibits growth and decreases viability E. coli EC958, but non-illuminated (CORM) is without effect. NADH-supported respiration rates are significantly decreased by activated PhotoCORM, mimicking effect dissolved CO gas. from binds...
Vibrational spectroscopy in supersonic jet expansions is a powerful tool to assess molecular aggregates close ideal conditions for the benchmarking of quantum chemical approaches. The low temperatures achieved as well absence environment effects allow direct comparison between computed and experimental spectra. This provides potential data which can be revisited hone different computational techniques, it allows critical analysis procedures under setting blind challenge. In latter case,...
The cytochrome b6f complex (b6f) links photosystem I (PSI) and II (PSII) in the photosynthetic electron transfer chain is distributed across appressed non-appressed thylakoid membranes. also activates state-transition 7 kinase (STT7), which phosphorylates light-harvesting proteins, triggering their migration to enable energy redistribution between PSII PSI. STT7-dependent phosphorylation has been observed at T4 N-terminal domain of subunit-IV (PetD), though its functional significance...
Molecular association of chloroform with ammonia is studied by high-level quantum chemical calculations including correlated MP2 and CCSD(T) basis sets up to6-311++G(d,p) counterpoise corrected energies, geometries, frequencies. The predict an eclipsed hydrogen-bonded complex C(3v) symmetry (DeltaE(0)=-15.07 kJ mol(-1)) 225.4 pm intermolecular CHcdots, three dots, centeredN distance. Intermolecular interactions are analysed Kitaura-Morokuma [Int. J. Quantum Chem. 10, 325 (1976)] interaction...
Cavity-enhanced resonant photoacoustic spectroscopy with optical feedback cw diode lasers (OF-CERPAS) is introduced as a novel technique for ultratrace gas analysis and high-resolution spectroscopy. In the scheme, single-mode laser (3 mW, 635 nm) coupled into high-finesse linear cavity stabilized to by feedback. Inside cavity, build-up of power at least 2.5 W occurs. Absorbing phase species inside are detected high sensitivity effect using microphone embedded in cavity. To increase further,...
The ν2+2ν3 combination band of CH412 near 7510 cm−1 was studied with the recently introduced technique cavity ring-down spectroscopy employing a cw-diode laser in pulsed supersonic slit jet expansion and Doppler-limited Fourier-transform infrared at room temperature. is strongest absorption high-wave-number region N=2.5 icosad methane. First assignments are provided. vibrational origin 7510.3378±0.0010 cm−1, integrated strength G=(1.3±0.2)×10−4 pm2 transition moment |μν|=(1.0±0.1)×10−3 D...
A molecular association between chloroform and sulfur dioxide in the gas phase at room temperature was studied by Fourier transform infrared spectroscopy. Since intensity of CH-stretching fundamental vibration monomer is very weak but much stronger upon complexation, a simple subtraction procedure isolated spectrum complex. The presence 1:1 complex confirmed two dilution series, where concentrations were varied. manifested itself as shift peak absorbance CHCl3–SO2 +7cm−1 CD-stretching...
We describe the construction and performance of an inexpensive modular Raman spectrometer that has been assembled in framework a fourth-year undergraduate project (costs below $5000). The is based on 4 mW 532 nm green laser pointer compact monochromator equipped with glass fiber optical connections, linear detector array, USB computer connection power supply. Because its backscattering geometry, can be used for liquid solid samples offers spatial resolution 100 μm. With spectral ca. 20 cm−1,...
High level ab initio quantum chemical calculations have been performed on the association of chloroform with ammonia in gas phase (counterpoise corrected MP2 and coupled-cluster CCSD(T) 6-311++G(d,p) basis functions). Minimum energy equilibrium structures found for CHCl3–NH3 dimer, CHCl3–(NH3)2 trimer CHCl3–(NH3)3 tetramer. Association is characterised by a CH⋯N hydrogen bond between an molecule, further units attached bonds to electrostatic NH⋯Cl interaction chloroform. Cooperative effects...
Nanocrystalline hydroxyapatite (nanoHA) is the main hard component of bone and has potential to be used promote osseointegration implants treat defects. Here, using active pharmaceutical ingredients (APIs) such as ibuprofen, we report on prospects combining nanoHA with biologically compounds improve clinical performance these treatments. In this study, designed investigated possibility API attachment surface crystals via formation a hydrogen-bonded complex. The mechanistic studies an...
Recently we introduced cavity-enhanced Raman spectroscopy (CERS) with optical feedback cw-diode lasers as a sensitive analytical tool. Here report improvements made on the technique and its first application in biosciences for situ, multicomponent, isotope selective gas measurements to study hydrogen production consumption by Escherichia coli. Under anaerobic conditions, cultures grown rich media supplemented d-glucose or glycerol produce H2 simultaneously consume some of it. By introducing...
Escherichia coli is a facultative anaerobe that can grow in variety of environmental conditions. In the complete absence O 2 , E. perform mixed-acid fermentation contains within it an elaborate metabolism formic acid. this study, we use cavity-enhanced Raman spectroscopy (CERS), FTIR, liquid spectroscopy, isotopic labelling and molecular genetics to make advances understanding bacterial formate H metabolism. It shown that, under anaerobic (anoxic) conditions, acid generated endogenously,...
Abstract Despite an absence of conventional porosity, the 1D coordination polymer [Ag 4 (O 2 C(CF ) CF 3 (TMP) ] ( 1 ; TMP=tetramethylpyrazine) can absorb small alcohols from vapour phase, which insert into AgO bonds to yield polymers (ROH) 1‐ROH R=Me, Et, i Pr). The reactions are reversible single‐crystal‐to‐single‐crystal transformations. Vapour‐solid equilibria have been examined by gas‐phase IR spectroscopy K =5.68(9)×10 −5 (MeOH), 9.5(3)×10 −6 (EtOH), 6.14(5)×10 PrOH) at 295 K, bar)....
Photoacoustic spectroscopy in a differential Helmholtz resonator has been employed with near-IR and red diode lasers for the detection of CO2, H2S O2 1 bar air/N2 natural gas, static flow cell measurements. With distributed feedback (DFB) laser, can be detected at 764.3 nm noise equivalent limit 0.60 mbar (600 ppmv) air (35-mW 1-s integration), corresponding to normalised absorption coefficient α = 2.2 × 10-8 cm-1 W s1/2. Within tuning range DFB laser (6357-6378 cm-1), CO2 features accessed,...
Overtone spectroscopy in the gas phase by vibrationally assisted dissociation and photofragment ionization (OSVADPI) has been coupled with mass spectrometric detection of fragments enabling us to separate congested spectra into components arising from several naturally occurring isotopomers. The new technique isotope selective overtone (ISOS) applied 41 component CH chromophore absorption near 11 385 cm−1 CHCl3 at room temperature supersonic jet expansions. These allow assign a close local...
The near-infrared overtone spectra of the prototypical hydrogen-bond hydrogen fluoride dimer (HF)2 contain rich information on bond dynamics. We report a study N = 2 triad involving excitations with two quanta HF stretching in around 1.3 μm (7500−7800 cm-1) by means continuous-wave-diode laser cavity ring-down spectroscopy pulsed supersonic slit jet expansion. analysis rotationally resolved allows vibrational mode-selective kinetics, such as predissociation lifetimes τPD and tunneling...