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A status report is presented about the Nanoplasmonic Laser Induced Fusion Experiment (NAPLIFE). The goal is to investigate and verify plasmonically enhanced phenomena on the surfaces of nanoantennas embedded in a polymer target at laser intensities up to a few times 1016 W/cm2 and pulse durations of 40–120 fs. The first results on enhanced crater formation for Au-doped polymer targets are shown, and SERS signals typical for CD2 and ND bound vibrations are cited. Trials to detect D/H ratio by means of LIBS measurments are reported. Plasmonics has the potential to work at these intensities, enhancing the energy and deuterium production, due to thus far unknown mechanisms.

The temperature dependence of the thermal conductivity k(T) of the AsxS100-x glass system was studied down to 1.8 K in a wide range of various (x = 20, 28.6, 40, 45, and 50) compositions. Universal glass anomalies in k(T) were revealed. The temperature dependence k(T) ∼ T2 onset at the lowest temperatures and plateau below 15 K were detected. The plateau formation is sample quality sensitive and composition-dependent. It was experimentally found that even with a slow cooling rate, several samples were cracked. Depending on the sample damage, the additional internal scattering process leads to the k(T) plateau suppression. The observed k(T) temperature dependence is similar to the glassy ceramics-like behavior.

In this work, we present the laser cleaning of a Rubidium vapor cell and the Raman analysis of the contaminant material to be removed. The optical window of the vapor cell had gradually lost transparency due to the development of an opaque layer of unknown composition at the inner side during the normal operation of the cell. Laser cleaning was successfully performed by a frequency-doubled Nd:YAG laser focusing the beam inside the cell, avoiding any possible damage to the window. A single laser pulse was enough to clear away the black discoloration at the focal spot and locally restore the transparency of the window. The Raman spectra of the deposit showed peaks not yet described in the literature. Comparison with known Rubidium germanate spectra and simulation results strongly suggested that the unknown material was Rubidium silicate.

The effect of tissue optical clearing (TOC) to increase the probing depth and observe in-depth structure of the ex vivo porcine dura mater was studied by confocal Raman microspectroscopy (CRM). Raman intensities were significantly increased at the depth of 250 μm for all collagen bands after treatment with glycerol. The influence of glycerol on collagen hydration was also investigated. The results indicate that the process of TOC can be divided into three main steps. The first one is a fast process of tissue dehydration accompanied by collagen shrinkage while the second relatively slow process is related to the glycerol penetration into the interfibrillar space of collagen combined with swelling of tissue. The third step is collagen dissociation caused by the high concentration of glycerol. To the best of our knowledge, this study is the first example to introduce the TOC technique in assisting CRM of ex vivo dura mater in-depth probing.

Two methods were proposed and implemented for the fabrication of channel waveguides in an Er-doped Tellurite glass. In the first method, channel waveguides were fabricated by implanting 1.5 MeV and 3.5 MeV energy N+ ions through a special silicon mask to the glass sample at various fluences. Those waveguides implanted at a fluence of 1.0 × 1016 ions/cm2 operated up to 980 nm, and showed green upconversion of the Erbium ions. In the second method, channel waveguides were directly written in the Er3+: TeO2W2O3 glass using an 11 MeV C4+ ion microbeam with fluences in the range of 1 · 1014–5 · 1016 ions/cm2. The waveguides worked in single mode regime up to the 1540 nm telecom wavelength. Propagation losses were reduced from the 14 dB/cm of the as-irradiated waveguides by stepwise thermal annealing to 1.5 dB/cm at λ = 1400 nm.

Confocal Raman microspectroscopy (CRM) with 633- and 785-nm excitation wavelengths combined with optical clearing (OC) technique was used for ex-vivo study of porcine skin in the Raman fingerprint region. The optical clearing has been performed on the skin samples by applying a mixture of glycerol and distilled water and a mixture of glycerol, distilled water and chemical penetration enhancer dimethyl sulfoxide (DMSO) during 30[Formula: see text]min and 60[Formula: see text]min of treatment. It was shown that the combined use of the optical clearing technique and CRM at 633[Formula: see text]nm allowed one to preserve the high probing depth, signal-to-noise ratio and spectral resolution simultaneously. Comparing the effect of different optical clearing agents on porcine skin showed that an optical clearing agent containing chemical penetration enhancer provides higher optical clearing efficiency. Also, an increase in treatment time allows to improve the optical clearing efficiency of both optical clearing agents. As a result of optical clearing, the detection of the amide-III spectral region indicating well-distinguishable structural differences between the type-I and type-IV collagens has been improved.

Experimental and theoretical studies were performed on Boson peak of binary AsxS100−x glasses and As–S polycrystalline composites (mixtures of glass with polycrystallites) of different compositions. Low-frequency Raman spectra of six different compositions ranging from As6S94 to As60S40, including the stoichiometric As40S60 composition, were measured in the region of 5–100 cm−1. The Fourier-transform Raman spectra of the As–S samples in the range of 50–600 cm−1 were also measured to reveal the structure of the materials at nanoscale. In addition, density functional theory calculations were performed on different As–S nanoclusters for determination of their low-frequency vibrational modes. The effect of the structural interconnection of the clusters on their vibrational mode frequencies was modeled by attaching different numbers of heavy dummy hydrogen atoms to the dangling bonds of branchy—As2+4/3S5 and 12-membered ring-like As6S6+6/2 nanoclusters. It was found that the vibrational mode frequencies have a U-shaped dependence on the level of interconnection, which correlates with experimental findings on compositional dependence of the Boson peak position in AsxS100−x glasses. The composition dependence of spectral behavior and very low-frequency features detected at low-energy side of the Boson peak in the Raman spectra of As–S samples were also analyzed and their structural origin is discussed.

Gold nanoparticle assisted thermally initiated chemical vapor deposition was used to synthesize nanostructured As-S films. The nanostructures were grown on heated Si substrates covered by spherical gold nanoparticles of different (5, 20, 40 and 60 nm) sizes. In contrast to polycrystalline As-S films prepared by ordinary thermal evaporation and chemical vapor deposition of As2S3 glass without the use of gold nanoparticles, the gold nanoparticle assisted synthesis leads to growth of particular type of crystal-like As-S nanostructures. The As-S micro-crystallites with well-defined size and shape were obtained with 43.9 and 56.1 at.% As and S atomic content, respectively. The local structure of the As-S microcrystallites was investigated by Raman and/or surface-enhanced Raman spectroscopy. To assist the interpretation of the experimental Raman spectra and to identify the structure of the crystallites, the vibrational spectra of different cage-like nanocluster models were also calculated by using the density functional theory. Results show that at specific deposition conditions a stimulated formation of As4S5 molecules occurs which activates the growth of micro-crystallites on the gold nanoparticle coated Si surface with well distinguished shape. The structure and properties of nanostructured As-S films synthesized with and without the use of gold nanoparticles were investigated and the gold nanoparticle assisted selective growth of a new type of As-S microcrystallite is discussed.

Composition and bonding configuration of silicate glasses with different lithium content was studied by laser induced breakdown spectroscopy and Raman spectroscopy. The lithium content of the formed glass matrix has been determined by using laser induced breakdown spectroscopy with high precision. Analysis of the Raman spectra implied on the complex character of lithium incorporation into the glassy matrix with lithium content. It was found that the addition of lithium results in more depolymerized SiO4 structures and, in general, increases the disorder of the structure. However, at certain concentrations lithium has an ordering effect due to more homogeneous size distribution of structural units of the glass matrix.

We have studied the light emission properties of aged glassy (g-) and crystalline (c-) As 2 S 3 and freshly fractured glassy As 2 S 3 with photosensitive realgar inclusions in the 1.5–4.5 eV spectral range and applying different excitation photon energies. Additionally, Raman scattering measurements were performed on g-As 40 S 60 to investigate structural changes caused by corrosion of the glass in air. Major features in the luminescence spectra were observed at 1.65, 1.87, 2.04, 2.26, 2.80 and 3.25 eV photon energies. The 1.65 eV band in photoluminescence spectra of g-As 2 S 3 was identified to be related to the As side by comparison of the photoluminescence spectrum with literature data for As 4 S 4 realgar crystal. A newly observed band at 1.87 eV was assigned to the As side in pararealgar occurring due to the light induced transformation from realgar to pararealgar phase. An oxidation process was found to take place during the aging and photo-aging accompanied with formation of As oxides, indicated by the emission bands at 2.04 and 2.26 eV. A rapid photo-oxidation process was observed in freshly fractured surfaces at room temperature which was connected with the light stimulated realgar-pararealgar transformation.

Reversible structural changes of As-rich As–Se nanolayers occurring during in situ thermal annealing and above-bandgap laser illumination were studied by synchrotron radiation photoelectron spectroscopy. It was found that the first thermal annealing of As56Se44 nanolayers led to a decrease of the concentration of As that can be connected with evaporation of more volatile As-rich fractions from the surface. This process is accompanied by structural rearrangements in the nanolayers. In situ green laser illumination of annealed samples causes an increase in the concentration of homopolar As–As bonds associated with As-Se2As s.u., while the opposite effect was detected during further thermal treatment. These processes appeared to be reversible for three sequences of annealing and illumination. The observed effect of the reversible photoinduced structural modification is discussed in detail, and possible applications as an active optical medium for photonics are proposed.

The surfaces of As20Se80, As40Se60 and As50Se50 films were studied using synchrotron radiation photoelectron spectroscopy and DFT electronic structure calculations. The composition and local structure of the surfaces were determined by curve fitting of the experimental As 3d and Se 3d core levels, and studies show significant Se-enrichment in the top surface layers of the films. The valence band spectra have been interpreted within a model of discrete structural units, giving rise to distinct peaks in the spectra. The interconnection between the surface composition, local structure formation and the features of the valence band spectra of As20Se80, As40Se60 and As50Se50 films is analyzed and discussed in detail.

The atomic composition, local structure and coordination of flash evaporated Ge2S3 films and their changes induced by laser illumination and thermal annealing in vacuum were investigated by means of high resolution synchrotron radiation and X-ray photoelectron spectroscopy. The top surface and subsurface layers of the films are found to be enriched by Ge in comparison with the composition of target glass and contain oxygen and a significant contribution of physisorbed carbon. The influence of laser and thermal treatments of flash evaporated Ge–S films in vacuum on their composition is analyzed. The local atomic coordination obtained by curve fitting of Ge 3d, S 2p, O 1s and C 1s core level spectra is discussed in detail.

Ab initio DFT calculations were performed on GenSem nanoclusters (n = 2, 3, 5, 6, 12; m = 6–9, 14, 16, 30) that represent the local structure of GeSe2 glass and on some ‘defect’ GenSem clusters that are thought to be related to the inhomogeneity of the structure at the nanoscale. The optimal geometries, total energies and their derivatives as well as the electronic properties of GenSem nanoclusters were calculated using traditional DFT method. In addition, the TD-DFT method has been applied to calculate the electronic band gaps of the clusters. The calculated physico-chemical properties of GenSem nanoclusters and their couplings with the local-and medium-range order structure formations in GeSe2 glass are analysed and discussed.

The influence of air and near bandgap laser irradiation on the surface structure of As40Se60 nanolayers has been investigated by synchrotron radiation photoelectron spectroscopy (SRPES). The As 3d and Se 3d photoemission peaks of the irradiated sample show significant differences in shapes and positions in comparison with those obtained for non-irradiated amorphous films. The experimental data processing and quantification were performed by analyzing As 3d, Se 3d, C 1s and 0 1s core-level components obtained by curve fitting. The relative contribution of the As, Se, C and 0 atoms in different chemical states to the whole As 3d, Se 3d, C is and 0 is signals, its structural origins as well as their relation to the As40Se60 surface and subsurface nanolayers structure before and after laser irradiation is analyzed and discussed in detail. An atomic model of induced structural changes on the surface of As40Se60 nanolayers under ambient conditions and after laser irradiation in air is proposed. (C) 2012 Elsevier B.V. All rights reserved.

The influence of near bandgap laser irradiation on the structure of the As50Se50 thin film has been investigated by synchrotron radiation photoelectron spectroscopy. The As 3d and Se 3d photoemission peaks of the irradiated sample show significant differences in shapes and positions in comparison with those obtained for non-irradiated amorphous film. The experimental data processing and quantifications are performed analyzing As 3d and Se 3d core-level components obtained by curve fitting. The relative contribution of the As and Se atoms in different chemical states to the whole As 3d and Se 3d signal, its structural origins as well as their relation to the As50Se50 nanolayers structure before and after laser irradiation is analyzed and discussed in detail.

Light-induced structural changes of As-S glasses and films were probed both by macro FT-Raman and photon-energy dependent micro-Raman spectroscopy using different spectral composition of photoactive light: polychromatic or different wavelengths of laser radiation. The polychromatic illumination and thermal treatment leads to continuous decrease in intensity of characteristics vibrational modes of molecular or cage-like species like As4S4, As4S3, etc. Under laser illumination the picture is different, new observed features in the Raman spectra of As-rich As-S glass are related to transformations of As4S4 molecules: α(β)-As4S4 transform into pararealgar p -As4S4 form during laser illumination. The effectiveness of transformations depends mainly on photon energies used for irradiation, but the tendency to transform is observed for all used photon energies ranging from 1.65 to 2.54 eV. Experimental photon-energy dependent Raman spectroscopy used together with ab initio DFT calculations indicate that the mechanism of photo-induced changes in As-S glasses and films is defined by spectral width of illumination source (© 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)

The non-linear two-photon absorption coefficient (TPA) of ternary Ge-As-S glasses of different sections (As2S3-GeS2, As2S3-Ge2S3, As-GeS2, As-Ge2S3) was measured at 690 nm. The obtained data were interpreted based on the evolution of the glass structure and mean coordination number with the composition. Raman spectroscopy was used to investigate the bonding configuration of the glasses and the structural interpretation of the vibrational bands was performed based on DFT calculations of vibrational spectra of different types of As(Ge)nSm clusters and XPS measurements. It was found that the TPA is decreasing near the magic coordination numbers of 2.4 and 2.67. Relationship between TPA and nanophase separation in ternary glasses is discussed. (© 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)

Imidazolium-based ionic liquids (ILs) involving anions of variable coordinating strength have been investigated using infrared (IR) and Raman spectroscopies, density functional theory (DFT) calculations and selective deuteration of the imidazolium CH groups. Particular emphasis has been placed on the vibrational assignments of the anion and cation internal vibrations, a prerequisite before any interpretation of spectral changes due to ion-ion interactions in these unconventional liquids. The vibrations of highly symmetric and weakly coordinating anions, such as PF(6)(-), have unperturbed wavenumbers, but unexpected IR or Raman activity for some modes, showing that the anion is subjected to an anisotropic electric field. The stretching as well as the in-plane and out-of-plane bending modes of the imidazolium CH groups are anharmonic. They give broad bands that reflect a large distribution of interactions with the surrounding anions. All the bending modes are mixed with ring vibrations and the stretching modes are complicated by Fermi resonance interactions with overtones and combination of in-plane ring modes. However, the stretching vibration of the quasi-diatomic C((2))-D bond appears to be a good spectroscopic probe of the increasing cation-anion interactions when the coordinating strength of the anion increases. The broad absorption observed in the far IR with weakly coordinating anions remains practically unchanged when the acidic C((2))-H imidazolium bond is methylated and even when the imidazolium cation is substituted by tetra-alkyl ammonium or pyrrolidinium cations. It is concluded that this absorption is a general feature of any IL, coming from the relative translational and librational motions of the ions without needing to invoke C((2))-H anion hydrogen bonds.

The super-bandgap laser irradiation of the in situ prepared As-S chalcogenide films was found to cause drastic structural transformations and unexpected selective diffusion processes, leading to As enrichment on the nanolayer surface. Excitation energy dependent synchrotron radiation photoelectron spectroscopy showed complete reversibility of the molecular transformations and selective laser-driven mass transport during "laser irradiation"-"thermal annealing" cycles. Molecular modeling and density functional theory calculations performed on As-rich cage-like clusters built from basic structural units indicate that the underlying microscopic mechanism of laser induced transformations is connected with the realgar-pararealgar transition in the As-S structure. The detected changes in surface composition as well as the related local and molecular structural transformations are analyzed and a model is proposed and discussed in detail. It is suggested that the formation of a concentration gradient is a result of bond cleavage and molecular reorientation during transformations and anisotropic molecular diffusion.

The comparative analysis of the calculated and experimental Raman spectra of non-crystalline As2S3, Bi2S3 and Sb2S3 films (i.e. with exchanging As to Sb, Bi) obtained by flash evaporation on glassy and silicon substrates was performed. The spectra were interpreted and analysed using the results of molecular modelling and ab initio calculations. The structural models used for calculations include both basic building blocks and other types of atomic clusters known for As-S, Bi-S, and Sb-S binary systems. The influence of atomic substitution on the nanostructure of flash evaporated As(Sb,Bi)2S3 films were investigated, observed photo-induced phenomena and related peculiarities were analysed using results of ab initio calculations and discussed in detail. (© 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)

The origin of the Boson peak was investigated using Raman spectroscopy and ab initio calculations. Low frequency Raman active vibrational modes of different branchy-, ring- and cage-like AsmSn nanoclusters were calculated and compared to experimentally determined Raman spectra of AsxS100-x glasses with different compositon. A good correlation was found between the spectral features and the calculated Raman modes. The possible structural nature of the Boson peak in arsenic chalcogenides is proposed and discussed.

As a probe of local structure, the vibrational properties of the 1-butyl-3-methylimidazolium tetrafluoroborate [bmim][BF4] ionic liquid were studied by infrared (IR), Raman spectroscopy, and ab initio calculations. The coexistence of at least four [bmim]+ conformers (GG, GA, TA, and AA) at room temperature was established through unique spectral responses. The Raman modes characteristic of the two most stable [bmim] + conformers, GA and AA, according to the ab initio calculations, increase in intensity with decreasing temperature. To assess the total spectral behavior of the ionic liquid both the contributions of different [bmim] + conformers and the [bmim]+- [BF4]- interactions to the vibrational spectra are discussed.

The calculated and experimental Raman spectra of the (EMI+)TFSI− ionic liquid, where EMI+ is the 1-ethyl-3-methylimidazolium cation and TFSI− the bis(trifluoromethanesulfonyl)imide anion, have been investigated for a better understanding of the EMI+ and TFSI− conformational isomerism as a function of temperature. Characteristic Raman lines of the planar (p) and non-planar (np) EMI+ conformers are identified using the reference (EMI+)Br− salt. The anion conformer of C2 symmetry is confirmed to be more stable than the cis (C1) one by 4.5 ± 0.2 kJ mol−1. At room temperature, the population of trans (C2) anions and np cations is 75 ± 2% and 87 ± 4%, respectively. Fast cooling quenches a metastable glassy phase composed of mainly C2 anion conformers and p cation conformers, whereas slow cooling gives a crystalline phase composed of C1 anion conformers and of np cation conformers. Copyright © 2006 John Wiley & Sons, Ltd.

Light-induced structural changes of g-As 40 S 60 and g-As 45 S 55 were probed by macro FT-Raman and photon-energy dependent micro-Raman spectroscopy. We hypothesize that some new observed features in the Raman spectra of these glasses are related to transformations of As 4 S 4 molecules possible through the m-As 4 S 4 intermediate. At the same time, other processes, connected mainly with the layers, composed of pyramidal AsS 3 structural units, take place. These new observed Raman modes and their possible interconnection to changes of the glassy structure are discussed.

We have used resonant Raman and absorption edge spectroscopy together with first-principle calculations in order to study the structure of GeS2 glasses (g-GeS2). The glasses were prepared under different melt temperatures and cooling rates, which are shown to significantly influence the g-GeS2 structure at the nano-scale. The combined use of Raman spectroscopy and ab initio calculations reveals the origin of the molecular level electronic structure and its connection to the interesting technological features of the g-GeS2. Local structure within the glasses is discussed in terms of atomic Ge n S m clusters. The band gaps computed for these clusters and their correlation to the experimental band gaps and the possible formation of band tail states are also discussed.

This paper is aimed at combining quantum-chemical calculations of the frequency spectra of clusters and spectroscopic studies of vibrational spectra of GeS2 glasses, obtained at different conditions, and films, prepared on their base. The optimized geometries and Raman spectra of edge- and corner-sharing, and ethane-like Ge–S clusters have been obtained from ab initio calculations with RHF/6–31G* basis set. The most intensive bands of calculated Raman spectrum of such clusters are in good agreement with experimental Raman data.

The results of comparison of spectral position of the LF bands of g-As2S3 and g-As22S78 with theoretical calculations of vibrational spectra of different clusters (As2S4, As2S5, As2S6, AsS3–As3) in the LF region (10–85 cm−1) are given. The torsion type vibrations of the small chain-like clusters are located in the same spectral region as Boson peak of As–S glasses system. They can make several contributions to the LF spectrum. The cluster lengths by weight distribution functions f(L)*L are from 5.5 to 10.1 A and from 4.5 to 7.5 A for g-As2S3 and g-As22S78, respectively. The lognormal fittings of the f(L)*L functions give the most probably values about the 7.6 A (for g-As2S3) and 6.2 A (for g-As22S78).

Technologically modified g-GeS 2 (TiVj) glasses prepared by melt quenching from different temperatures (T i ) and with different cooling rates (Vj) were studied using Raman spectroscopy and model calculations. Differential Raman spectra {I R GeS 2 (T i V 1 )-I R GeS2(T 2 V 1 )} showed the splitting of the main, most intensive wide-band, centered at 340 cm -1 . The position of the peaks found in the differential Raman spectra near 340 and 360 cm -1 and position of the main vibrational modes in the ordinary Raman spectra of low- and high-temperature crystalline phases (α-, β-GeS2) were found to be in good agreement. Vibrational spectra of 4- and 6-member ring fragments selected from crystalline structure of β-GeS 2 were also determined using model calculations. Based on rings composed of GeS 4 tetrahedrons connected by corners and edges the structural interpretation of the vibrational bands of g-GeS 2 (TiVj) at 360, 370 and 433 cm -1 in their Raman spectra was performed. The existence of homopolar Ge-Ge and S-S “defect” bonds in the structure of germanium disulfide glasses was proved by formation of 5-member rings. Formation of fragments of both low- and high-temperature α-, β-GeS 2 crystalline phases in the structure of g-GeS 2 (TiVj) glasses indicates the existence of mixed medium-range ordering in g-GeS 2 .

As-deposited, annealed, and in situ As2S3 nanolayers, illuminated by blue (405 nm) and red (650 nm) laser light, were studied using synchrotron radiation photoelectron spectroscopy and DFT electronic structure calculations. Changes in composition and local atomic coordination occurring in the irradiated region of As2S3 films were monitored by analysis of As 3d and S 2p core levels. These studies show that both the thermal treatment and the red laser illumination of As2S3 nanolayers decrease the concentration of homopolar (As-As and S-S) bonds. From the other hand, an increasing concentration of As-rich structural units (s.u.) with a homopolar As-As bond was observed under in situ blue laser illumination of As2S3 nanolayers. Molecular orbital energies were calculated for different As- and S-centered s.u. and used for the interpretation of the core levels and valence band spectra. The surface local structure of the As2S3 nanolayers and its photoinduced transformation are discussed in detail.

The effect of lithium ion coordination with the bis(oxalato)borate (BOB-) [B(C2O4)2]- anion in DMSO, PEG, PPG, and d-PPG has been studied in detail by IR and Raman spectroscopy. Ab initio calculations were performed to allow a consistent analysis of the experimental data. The main features observed in the IR and Raman spectra correspond to the presence of "free", un-coordinated, BOB- anions. Only with use of d-PPG as solvent a small amount of Li+...BOB- ion pairs were detected. The Raman spectra and the calculations together indicate that Li+ coordinates bidentately with two end-oxygen atoms of the BOB- anion. The identification of ion pairs can be used to reveal limitations of LiBOB based electrolytes. The results for LiBOB are compared with literature on other Li salts.