Laser Irradiation of Polymer-Doped Cryogenic Matrices

Rodrigo, Katarzyna Agnieszka; Toftmann, B.; Schou, Jørgen; Pędrys, R.

doi:10.1007/s10909-005-5480-0

Cited by 22 publications

(5 citation statements)

References 26 publications

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“…However, these processes were found to be dominant for laser intensities 1−2 orders of magnitude higher as compared to our experiments. 27,28 Conversely, during the irradiation of the frozen targets nonhomogeneous absorption processes can take place. 29 The laser radiation is absorbed by the material of interest, TiO 2 NPs and GO platelets, similarly to the process described in ref 30 for benzene−water mixture.…”

Section: Introductionmentioning

confidence: 99%

Resonant Infrared and Ultraviolet Matrix-Assisted Pulsed Laser Evaporation of Titanium Oxide/Graphene Oxide Composites: A Comparative Study

et al. 2014

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Pure titanium dioxide (TiO 2 ) and graphene oxide (GO) as well as TiO 2 / GO composite structures were grown by matrix-assisted pulsed laser evaporation (MAPLE) in a controlled oxygen atmosphere. The MAPLE target dispersions were prepared using distilled water as solvent matrix, with TiO 2 nanoparticles (NPs) and GO platelets serving as host materials. Two laser sources, a free-running IR Er:YAG (λ = 2940 nm, τ fwhm ≅ 350 μs, ν = 10 Hz) and a UV KrF* excimer (λ = 248 nm, τ fwhm ≅ 25 ns, ν = 10 Hz) laser, were used for the transfer and immobilization experiments by infrared (IR)-and ultraviolet (UV)-MAPLE, respectively. The potential physical mechanisms implied in both the IR-and UV-MAPLE processes are discussed, based on numerical simulations of temperature evolution of the distilled water matrix, TiO 2 NPs, and GO platelets. Our results demonstrate the effectiveness of IR-and UV-MAPLE processes for the immobilization of nanoentities onto solid substrates. During IR-MAPLE, the laser radiation is primarily absorbed by the water matrix. The materials transferred to the substrate surface resemble the initial starting materials used for the preparation of the MAPLE target dispersions. Conversely, during UV-MAPLE the UV radiation is mainly absorbed by the nanoentities dispersed in the water matrix. The structural transformation of the nanoentities deposited by UV-MAPLE is significant as compared to the starting materials.

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Section: Introductionmentioning

confidence: 99%

Resonant Infrared and Ultraviolet Matrix-Assisted Pulsed Laser Evaporation of Titanium Oxide/Graphene Oxide Composites: A Comparative Study

et al. 2014

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“…25,26 The MAPLE technique has been successfully used to deposit uniform thin layers of small organic molecules and polymers (thickness from 10 nm to over 1 µm) with accurate thickness control (variations less than 0.05 nm/laser shot) and good to excellent structural fidelity. 3,14,[28][29][30][35][36][37][38][39][40][41][42][43][44][45][46][47][48][49][50] In MAPLE, a flash-frozen matrix consisting of a dilute solution (0.5 to 5.0 weight%) of the macromolecules in a relatively volatile and highly UV absorbing solvent is used as the laser target. Figure 2 shows a flash-frozen target of a first generation phosphorescent dendrimer (G1) 51 comprising a factris(2-phenylpyridyl) iridium(III) core, biphenyl dendrons, and 2-ethylhexyloxy surface groups (structure in Figure 13) in chloroform.…”

Section: Ultraviolet (Uv) Pld and Maplementioning

confidence: 99%

“…Skripov performed calculations based on Equation 44 for liquid metals and estimated the time lag to be approximately 1-10 ns. 137 The values are consistent with the low viscosity of a superheated liquid, which ensures quick relaxation of the system.…”

Section: Spinodal Decay As Precursor To Phase Explosionmentioning

confidence: 99%

Mechanisms of Resonant Infrared Matrix-Assisted Pulsed Laser Evaporation

Torres

Johnson

Haglund

et al. 2011

Critical Reviews in Solid State and Materials Sciences

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For the last decade, a variant of pulsed laser ablation, Resonant-Infrared Matrix-Assisted Pulsed Laser Evaporation (RIR-MAPLE), has been studied as a deposition technique for organic and polymeric materials. RIR-MAPLE minimizes photochemical damage from direct interaction with the intense laser beam by encapsulating the polymer in a high infrared-absorption solvent matrix. This review critically examines the thermally-induced ablation mechanisms resulting from irradiation of cryogenic solvent matrices by a tunable free electron laser (FEL). A semi-empirical model is used to calculate temperatures as a function of time in the focal volume and determine heating rates for different resonant modes in two model solvents, based on the thermodynamics and kinetics of the phase transitions induced in the solvent matrices.Three principal ablation mechanisms are discussed, namely normal vaporization at the surface, normal boiling, and phase explosion. Normal vaporization is a highly inefficient polymer deposition mechanism as it relies on collective collisions with evaporating solvent molecules. Diffusion length calculations for heterogeneously nucleated vapor bubbles show that normal boiling is kinetically limited. During high-power pulsed-FEL irradiation, phase explosion is shown to be the most significant contribution to polymer deposition in RIR-MAPLE. Phase explosion occurs when the target is rapidly heated (10 8 to 10 10 K/s) and the solvent matrix approaches its critical temperature. Spontaneous density stratification (spinodal decay) within the condensed metastable phase leads to rapid homogeneous nucleation of vapor bubbles. As these vapor bubbles interconnect, large pressures build up within the condensed phase, leading to target explosions and recoil-induced ejections of polymer to a near substrate. Phase explosion is a temperature (fluence) threshold-limited process, while surface evaporation can occur even at very low fluences.

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“…Vibrational spectroscopy is an essential tool in the study of hydration of biomolecules. − Much information can be obtained under cryogenic conditions, in which hydration and hydrated species are often studied experimentally, for example, in cryogenic matrices − or in molecular beams. − Such experiments typically result in sharply defined, well-resolved features, but, at the same time, have implications relevant also for ambient conditions. On the one hand, it is obviously important to understand properties at biologically relevant temperatures.…”

Section: Introductionmentioning

confidence: 99%

Hydrogenic Stretch Spectroscopy of Glycine–Water Complexes: Anharmonic Ab Initio Classical Separable Potential Calculations

2019

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The anharmonic frequencies of O−H, C−H, and N−H stretching modes of hydrogen-bonded glycine−H 2 O complexes are calculated using ab initio classical separable potential approximation. In this approach, ab initio molecular dynamic simulations are used to determine an effective classical potential for each of the normal modes of the system. The frequencies are calculated by solving the time-independent Schrodinger equation for each mode using time-averaged potentials. Three complex structures are studied, which differ in the location of the water molecule on the amino acid. Significant differences are found between the spectra of the three structures, and signatures of individual complexes are established. It is demonstrated that anharmonic effects are essential in the discrimination between different structures, while frequency differences at the harmonic level are much smaller. Intensities are also computed and found to carry information on differences between structures, but the role of anharmonicity in this is small.

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Laser Irradiation of Polymer-Doped Cryogenic Matrices

Cited by 22 publications

References 26 publications

Resonant Infrared and Ultraviolet Matrix-Assisted Pulsed Laser Evaporation of Titanium Oxide/Graphene Oxide Composites: A Comparative Study

Resonant Infrared and Ultraviolet Matrix-Assisted Pulsed Laser Evaporation of Titanium Oxide/Graphene Oxide Composites: A Comparative Study

Mechanisms of Resonant Infrared Matrix-Assisted Pulsed Laser Evaporation

Hydrogenic Stretch Spectroscopy of Glycine–Water Complexes: Anharmonic Ab Initio Classical Separable Potential Calculations

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