Infrared analysis of Glycine dissociation by MeV ions and keV electrons

2021 ◽  
Author(s):  
C A P da Costa ◽  
J A Souza-Corrêa ◽  
E F da Silveira
Keyword(s):  
Solar Wind ◽  
Cross Sections ◽  
Room Temperature ◽  
Stopping Power ◽  
Infrared Analysis ◽  
Absorbed Energy ◽  
Power Threshold ◽  
The Mean ◽  
Good Agreement ◽  
Electronic Stopping Power

Abstract Knowledge on amino acid's dissociation rates by solar wind is relevant for the study of biomaterial resistance in space. The radiolysis and sputtering of glycine by 1 keV electron beam and by 1.8 MeV H+, 1.5 MeV He+ and 1.5 MeV N+ ion beams are studied in laboratory, at room temperature. The column density decrease rates due to each beam are measured via infrared spectroscopy and destruction cross sections are determined. Present results stand in good agreement with those found in the literature and show that over five orders of magnitude, apparent destruction cross sections (which includes sputtering), σdap, are approximately proportional to the electronic stopping power, Se, that is (σdap ≈ a Se), where 1/a ≈ 120 eV/nm3. This value corresponds to the mean absorbed energy density necessary to dissociate (and/or eject) glycine; it also suggests that the stopping power threshold for molecular destruction is 23 keV μm−1. Assuming σdap = a Se for electron and ion projectiles, the half-life of pure α-glycine is estimated for the solar wind processing at 1 AU: about 10 days for protons or electrons and 40 days for He ions.

DYNAMICS OF THE N(2D)+H2 REACTION ON THE $\tilde{X}^2 A^{\prime\prime}$ SURFACE, PROPAGATING REAL WAVE PACKETS WITH AN ARCCOS MAPPING OF THE HAMILTONIAN

2003 ◽  
Vol 02 (04) ◽  
pp. 547-551 ◽  
Author(s):  
PAOLO DEFAZIO ◽  
CARLO PETRONGOLO
Keyword(s):  
Rate Constant ◽  
Cross Sections ◽  
Room Temperature ◽  
Wave Packets ◽  
Flux Analysis ◽  
Title Reaction ◽  
Angular Momentum Quantum Number ◽  
Insertion Mechanism ◽  
Temperature Rate ◽  
Good Agreement

We have investigated the dynamics of the title reaction with the Gray and Balint-Kurti approach, which propagates real wave packets (WP) under an arccos mapping of a scaled and shifted Hamiltonian. We have considered H 2 rotational quanta j=0 and 1 and obtained reaction probabilities using reactant coordinates and the flux analysis. We have calculated accurate reaction probabilities for total angular momentum quantum number J=0, centrifugal-sudden probabilities for J>0, cross sections, and the room temperature rate constant. The present cross sections are in good agreement with previous quasiclassical trajectory (QCT) results and the theoretical rate constant compares rather well with that observed. WP snapshots show that the reaction occurs via a C2v insertion mechanism, confirming previous QCT calculations.

scholarly journals The Dynamics of the S(1D)+H2/D2 Reactions at Low Temperature via Statistical Simulations

2020 ◽  
Vol 3 (1) ◽  
pp. 9-16
Author(s):  
Tomas Gonzalez-Lezana ◽  
Pascal Larrégaray ◽  
Laurent Bonnet
Keyword(s):  
Cross Sections ◽  
Quantum Model ◽  
Space Theory ◽  
Collisional Energy ◽  
Energy Regime ◽  
Phase Space Theory ◽  
The Mean ◽  
Statistical Approaches ◽  
Theoretical Results ◽  
Good Agreement

Two different statistical approaches, the statistical quantum model (SQM) and the mean potential phase space theory (MPPST), have been employed to calculate the integral cross sections for the reactive collisions between S(1D) and H2/ D2  in the low energy regime (below 0.3 eV collisional energy). The rate constant for the S(1D) + H2 → SH + H reaction has been also obtained and compared with previously reported experimental and theoretical results. The good agreement shows the capability of these two methods to study the dynamics of these complex-forming atom-diatom processes in the present energy regime.

scholarly journals Renormalised Perturbation Theory of Resonant Multiphoton Ionisation

1995 ◽  
Vol 48 (5) ◽  
pp. 835
Author(s):  
K Unnikrishnan
Keyword(s):  
Perturbation Theory ◽  
Cross Sections ◽  
Bound States ◽  
Resonance Region ◽  
Short Pulses ◽  
Total Cross Sections ◽  
Two Photon ◽  
Continuum States ◽  
The Mean ◽  
Good Agreement

Perturbation theory of multiphoton ionisation due to a classical electromagnetic field is modified to allow for intermediate resonances with bound states. Complex energies, generally associated with resonances, do not enter into this formalism. For a monochromatic field of frequency u, a constant ionisation rate can then be defined unambiguously and only such continuum states are excited which correspond to the absorption of energy in integral multiples of hu. As an application, differential and total cross sections for the two-photon ionisation of hydrogen, for frequencies below the n = 3 resonance region, are obtained in closed form. Existing data for generalised cross sections, calculated numerically using the complex coordinate method, are in good agreement with the present results. Finally, the mean fractional ionisation resulting from a pulse of finite duration is estimated on the basis of the associated power spectrum. For short pulses, the time dependence of ionisation exhibits a departure from that expected of a time-independent rate.

Electronic stopping power threshold of damage creation in yttrium iron garnet

1993 ◽  
Vol 126 (1-4) ◽  
pp. 251-254 ◽  
Author(s):  
A. Meftah ◽  
M. Hage-Ali ◽  
J. P. Stoquert ◽  
F. Studer ◽  
M. Toulemonde
Keyword(s):  
Yttrium Iron Garnet ◽  
Stopping Power ◽  
Yttrium Iron ◽  
Power Threshold ◽  
Iron Garnet ◽  
Electronic Stopping Power

Microstructure of Swift Heavy Ion Irradiated SiC, Si3N4 and AlN

2000 ◽  
Vol 650 ◽  
Author(s):  
S.J. Zinkle ◽  
J.W. Jones ◽  
V.A. Skuratov
Keyword(s):  
Room Temperature ◽  
Single Crystal Silicon ◽  
Heavy Ion ◽  
Stopping Power ◽  
Crystal Silicon ◽  
Swift Heavy Ion ◽  
Transmission Electron ◽  
Track Formation ◽  
Temperature Irradiation ◽  
Electronic Stopping Power

ABSTRACTCross-section transmission electron microscopy was used to investigate the microstructure of single crystal silicon carbide and polycrystalline silicon nitride and aluminum nitride following room temperature irradiation with either 245 MeV Kr or 710 MeV Bi ions. The fluences ranged from 1×1012/cm2 (single track regime) to 1×1013/cm2. Ion track formation was observed in the Bi ion-irradiated Si3N4 specimen in regions where the electronic stopping power exceeded a critical value of ∼15 keV/nm (depths <24 μm). Ion track formation was not observed at any depth in 245 MeV Kr ion-irradiated Si3N4, in which the maximum electronic stopping power was 14.5 keV/nm. There was no evidence for track formation in either SiC or AlN irradiated with 710 MeV Bi ions, which indicates that the threshold electronic stopping power for track formation in these two ceramics is >34 keV/nm. The high resistance of SiC and AlN to track formation may be due to their high thermal conductivity, but further study is needed to quantitatively evaluate the suitability of the various track formation models.

The Range Distribution of Nd Ions Implanted in Silicon-on-Insulator

2011 ◽  
Vol 306-307 ◽  
pp. 315-318
Author(s):  
Yi Liang ◽  
Hong Zhen Li ◽  
Shuang Li ◽  
Feng Xiang Wang ◽  
Xi Feng Qin
Keyword(s):  
Monte Carlo ◽  
Room Temperature ◽  
Silicon On Insulator ◽  
Monte Carlo Code ◽  
Experiment Data ◽  
Lateral Deviation ◽  
Projected Range ◽  
The Mean ◽  
The Difference ◽  
Good Agreement

In view of the influence of the projected range, the range straggling, and the lateral deviation of ions in materials on the property of photoelectric integration devices fabricated by ion implantation, the mean projected ranges and range straggling for energetic 200 – 500 keV neodymium (Nd) ions implanted in silicon-on-insulator (SOI) at room temperature were measured by means of Rutherford backscattering followed by spectrum analysis.The measured results are compared with Monte Carlo code (SRIM2006) predictions. Our results show that the measured values of the mean projected rangeRpare good agreement with the SRIM calculated values; for the range straggling ΔRp, the difference between the experiment data and the calculated results is much higher than that ofRp.

Measurement and Modeling of Intrinsic Stresses in CVD W Lines

1995 ◽  
Vol 391 ◽  
Author(s):  
Jin Lee ◽  
Qing Ma ◽  
Thomas Marieb ◽  
Anne S. Mack ◽  
Harry Fujimoto ◽  
...  
Keyword(s):  
Finite Element ◽  
Cross Sections ◽  
Room Temperature ◽  
Chemical Vapor ◽  
Intrinsic Stress ◽  
X Ray ◽  
Chemical Vapor Deposited ◽  
Biaxial Tensile Stress ◽  
Stress States ◽  
Good Agreement

AbstractWe have studied stress states in chemical vapor deposited (CVD) tungsten (W) for both blanket films and lines, to understand better the mechanical implications of intrinsic stress for interconnection structures. Since W has a low mobility at its deposition temperature, a very large intrinsic stress develops during deposition. Intrinsic strains in blanket W films were measured with an X-ray technique. The measured strains correspond to a biaxial tensile stress of the order of 1 GPa. This result was used to provide an initial strain input in a finite element calculation to obtain intrinsic stress states in W lines. SEM observation of cross sections of the metal lines enabled us to determine the growth pattern of the W, and infer the boundary conditions during growth. Finite Element Method (FEM) calculations of the room temperature stress in the lines, including both intrinsic and thermal components, are in good agreement with X-ray determinations.

The Mean Projected Range and Range Straggling of Yb Ions Implanted in Silicon Crystal

2012 ◽  
Vol 476-478 ◽  
pp. 1249-1253
Author(s):  
Xi Feng Qin ◽  
Hui Ning Wang ◽  
Zi Wu Ji ◽  
Feng Xiang Wang ◽  
Gang Fu
Keyword(s):  
Room Temperature ◽  
Silicon Crystal ◽  
Single Crystal Silicon ◽  
Monte Carlo Code ◽  
Experiment Data ◽  
Crystal Silicon ◽  
Projected Range ◽  
The Mean ◽  
The Difference ◽  
Good Agreement

The mean projected ranges and range straggling for energetic 200 – 500 keV Yb ions implanted in single crystal silicon (c-Si) at room temperature were measured by means of Rutherford backscattering followed by spectrum analysis. The measured results are compared with Monte Carlo code (SRIM2010) predictions. Our results show that the measured values of the mean projected range Rp are good agreement with the SRIM calculated values; but the difference of the range straggling ΔRp between the experiment data and the calculated results is much higher than that of Rp.

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