A5033372095- Laser-induced spectroscopy and plasma
- Atomic and Molecular Physics
- Laser-Matter Interactions and Applications
- Advanced Chemical Physics Studies
- Mass Spectrometry Techniques and Applications
- Porphyrin and Phthalocyanine Chemistry
- Electron and X-Ray Spectroscopy Techniques
- Advanced X-ray Imaging Techniques
- Metal complexes synthesis and properties
- Spectroscopy and Laser Applications
- Photochemistry and Electron Transfer Studies
- Particle Accelerators and Free-Electron Lasers
- Organometallic Complex Synthesis and Catalysis
- Magnetism in coordination complexes
- Diamond and Carbon-based Materials Research
- Mercury impact and mitigation studies
- CCD and CMOS Imaging Sensors
- Laser-Plasma Interactions and Diagnostics
- Laser Design and Applications
- Photodynamic Therapy Research Studies
- Nanoplatforms for cancer theranostics
- Photosynthetic Processes and Mechanisms
- Advanced Fluorescence Microscopy Techniques
- Advanced Optical Sensing Technologies
- X-ray Spectroscopy and Fluorescence Analysis
Dublin City University
2019-2024
University of Ioannina
2024
Abstract Spatial and temporal characteristics of a table-top scale laser produced plasma formed on the surface tungsten target are reported. The emitted radiation was spectrally filtered to narrow band ca. 1 nm (FWHM) centred wavelength 13.6 using combination Zr thin film transmission filters Mo-Si multilayer mirror (MLM). profile flux measured for different fluences while spatial emission sampled in one region back illuminated CCD, both done with aid flat MLM. emitting imaged at by...
Abstract New information demonstrating the importance of both sequential and simultaneous (or direct) multiphoton ionization inner shell electrons from neon is discussed in this paper. Ne was irradiated with intense 93 eV free electron laser (FEL) pulses at FLASH studied aid photoelectron spectrometry. This resulted two three photon, single double neon, removing 2s 2p subshells neutral atom multiple different pathways. The spectral features photoelectrons were identified through comparison...
Comparison of line plasma and point VUV laser induced breakdown spectroscopy for the detection carbon in steel.
Abstract Results of angle-resolved electron spectroscopy near-threshold photoionization Ne atoms by combined femtosecond extreme ultraviolet and near infrared fields are presented. The dressed-electron spectra show an energetic distribution into so-called sidebands, being separated the photon energy dressing laser. Surprisingly, for low kinetic (few eV) photoelectron varies as a function emission angle. Such behavior has not yet been observed in sideband creation predicted commonly used...
We have measured the photoabsorption spectra of Pb II and Bi III in wavelength range between 37 70 nm. A number features been identified with aid Cowan suite atomic codes. 5d → 6p transitions from ground configuration (5d106s26p) three excited configurations (5d106s26d, 5d106s27s, 5d106s6p2) give rise to most prominent spectra. Evidence states including (5d106s6p2 (4P3/2, 4D3/2)) for (4P1/2, 4P3/2)) was observed our measurements.
The effect of laser wavelength on the dissociation mechanisms in methane is examined over a broad range intensities for both 800 nm and 400 fields. It found that, at lower intensities, pathways identified with aid theoretical calculations cation can account most experimental findings, including differences observed irradiation by As intensity increases, significance Coulomb explosion mechanism, along contribution rescattering process concomitant pathways, highlighted.
We report angle-resolved measurements on photoelectrons emitted upon near-threshold two-photon double ionization (TPDI) of Kr irradiated by free-electron laser (FEL) pulses. These photoelectron angular distributions (PADs) are compared with the results semirelativistic $R$-matrix calculations. As reported Augustin et al. [Phys. Rev. A 98, 033408 (2018)], it is found that presence autoionizing resonances within bandwidth exciting FEL pulse strongly influences PADs. In contrast to lower-$Z$...
This study presents the development and characterization of a novel porphyrin-Jeffamine polymer conjugate designed to function as photosensitizer prodrug for antimicrobial photodynamic therapy (aPDT). The features photosensitive porphyrin unit covalently attached biocompatible backbone, with enhanced solubility, stability, bioavailability compared those free derivatives. photophysical properties were studied using transient absorption spectroscopy spanning fs-μs time scales in addition...
The photophysical properties of Cu(II) complexes with 5,10,15,20-meso-tetrakis(phenyl)porphyrin and 5,10,15,20-meso-tetrakis(N-methylpyridium-4-yl)porphyrin were examined by luminescence femtosecond time-resolved absorbance methods respectively. These studies supported DFT TD-DFT calculations which highlight the important role played a ligand-to-metal charge-transfer states in directing system towards either intersystem crossing to triplet hypersurface or coordinative expansion...
The photophysical properties of Cu(II) complexes with 5,10,15,20-meso-tetrakis(phenyl)porphyrin and 5,10,15,20-meso-tetrakis(N-methylpyridium-4-yl)porphyrin are examined via the luminescence femtosecond time-resolved absorbance methods, respectively. These studies supported by DFT TD-DFT calculations, which highlight important role played ligand-to-metal charge-transfer states in directing system toward either intersystem crossing to triplet hypersurface or coordinative expansion a...
It has been well established in the literature that surface contamination can adversely affect aerodynamic performance of aerofoils and hence efficiency with which turbines convert wind to electrical power. Hence it is critical ensure turbine blades are kept as free possible contaminants. In this manuscript, we discuss LIBS machine learning techniques on contaminated a view possibility integrating these methods into standoff laser ablation setup future. A signal will be key step decision...
An open-loop control scheme of molecular fragmentation based on transient alignment combined with single-photon ionization induced by a short-wavelength free electron laser (FEL) is demonstrated for the acetylene cation. Photoelectron spectra are recorded, complementing ion yield measurements, to demonstrate that such consequence changes in electronic response orientation relative ionizing field. We show stable C2H2+ cations mainly produced when molecules parallel or nearly FEL polarization,...
The photoabsorption spectrum of Bi+ was measured in the wavelength range between 37 and 60 nm, using dual laser plasma technique which one is used as source vacuum ultraviolet continuum radiation other sample atoms and/or ions to be probed. A number features identified with aid Cowan suite atomic codes. 5d → 6p transitions from ground configuration (5d106s26p2) gave rise most prominent spectrum. Transitions low-lying excited states associated four configurations, 5d106s26p6d, 5d106s26p7s,...
We report oxygen K-shell photoabsorption measurements in CO2 plasmas, using a table-top laser produced plasma soft X-ray and extreme ultraviolet (EUV) source. Significant differences are observed between the spectra of neutral molecule photoionized as new spectral features emerge case latter. These attributed to 1s → 2p photoexcitation O, O+ , O 2+ species identified with aid calculations performed Cowan suite atomic structure codes. Such signatures ions point fragmentation parent upon...
In this work we investigate the effect of confinement angle on self-colliding aluminium laser produced plasmas. More specifically, apply V-shaped channel targets different angles (90°, 60° and 30°) report both broadband filtered time-resolved fast imaging measurements formation such plasmas in ambient air. Based suggest that formed two inner walls expand normally to surface, interact with each other possibly stagnate. The spectrally reveals presence a spatial distribution species within...
Abstract We report on the first measurement of resonant three-step, two-colour ionization atomic molybdenum, using a hollow cathode lamp (HCL) with optogalvanic detection. Wavelength scans were made for two specific transitions involved in pathways under investigation, namely 4d 5 ( 6 S)5s 7 S 3 –4d S)5p P 4 and S)6d D . So-called ‘slow’ ‘fast’ signals respectively observed each quantum jump simultaneous excitation laser frequencies. This successful detection confirms HCL as cost effective...
Abstract In this work, we present measurements of the intensity-dependent photoelectron spectrum Kr irradiated by FLASH FEL tuned to a photon energy 25.8 eV. Intensity dependent spectra were obtained with aid Velocity Map Imaging (VMI) spectrometer. As is close threshold, two sequential double ionization favoured. The number open channels kept minimum and leading simple description process.
Irradiation of methane by intense laser fields leads to the production several molecular ions CH <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">n</sub> <sup xmlns:xlink="http://www.w3.org/1999/xlink">m+</sup> (m = 1, 2 with n 0-4) and atomic fragments such as H 0, 1 2) a result dissociation [1]. Previous studies on ionization irradiated pulses nanosecond duration [2] showed an absence parent fragment...
Abstract In this reply, we address the comments made by A N Ryabtsev on our paper (H Lu et al 2020 J. Phys. B: At. Mol. Opt. 53 115001). Specifically, emphasize that observed spectra depend critically plasma source type and conditions pertain in source. Our of ions experimental setup/method are quite different to one referred comment (A 2000 Spectrosc. 88 316–20). So there is no doubt contain evidence photoabsorption from low-lying excited states, their inclusion necessary, order account for...