Formation of different charge states and the charge state fractions of sputtered Ti and Ni

Results are presented of experiments on ion production from Ta targets using a short pulse (350–600 ps in focus) illumination with focal power densities exceeding 1014 Wcm-2 at the wavelength of an iodine photodissociation laser (1.315 μm) and its harmonics. Strong evidence of the existence of tantalum ions with the charge state +45 near the target surface was obtained by X-ray spectroscopy methods. The particle diagnostics point to the existence of frozen high charge states (<53+) of Ta ions in the far expansion zone at about 2 m from the target. The measured charge state-ion energy distribution indicates the highest energy (>4 MeV) for the highest observed charge states. A tentative theoretical explanation of the observed anomalous charge state freezing phenomenon in the expanding plasma produced by a subnanosecond laser pulse is given.

Download Full-text

Design of Peltier Element Based on Semiconductors with Hopping Electron Transfer via Defects

Devices and Methods of Measurements ◽

10.21122/2220-9506-2021-12-1-13-22 ◽

2021 ◽

Vol 12 (1) ◽

pp. 13-22

Author(s):

N. A. Poklonski ◽

S. A. Vyrko ◽

A. I. Kovalev ◽

I. I. Anikeev ◽

N. I. Gorbachuk

Keyword(s):

Charge State ◽

Energy Gap ◽

Energy Levels ◽

Practical Interest ◽

Band Gap Energy ◽

Structural Defects ◽

Band Model ◽

Peltier Element ◽

Intrinsic Defects ◽

Charge States

The study of thermoelectric properties of crystalline semiconductors with structural defects is of practical interest in the development of radiation-resistant Peltier elements. In this case, the spectrum of energy levels of hydrogen-like impurities and intrinsic point defects in the band gap (energy gap) of crystal plays an important role.The purpose of this work is to analyze the features of the single-electron band model of semiconductors with hopping electron migration both via atoms of hydrogen-like impurities and via their own point triplecharged intrinsic defects in the c- and v-bands, as well as to search for the possibility of their use in the Peltier element in the temperature range, when the transitions of electrons and holes from impurity atoms and/or intrinsic defects to the c- and v-bands can be neglected.For Peltier elements with electron hopping migration we propose: (i) an h-diode containing |d1)and |d2)-regions with hydrogen-like donors of two types in the charge states (0) and (+1) and compensating them hydrogen-like acceptors in the charge state (−1); (ii) a homogeneous semiconductor containing intrinsic t-defects in the charge states (−1, 0, +1), as well as ions of donors and acceptors to control the distribution of t-defects over the charge states. The band diagrams of the proposed Peltier elements in equilibrium and upon excitation of a stationary hopping electric current are analyzed.A model of the h-diode containing hydrogen-like donors of two types |d1) and |d2) with hopping migration of electrons between them for 50 % compensation by acceptors is considered. It is shown that in the case of the reverse (forward) electrical bias of the diode, the cooling (heating) of the region of the electric double layer between |d1)and |d2)-regions is possible.A Peltier element based on a semiconductor with point t-defects is considered. It is assumed that the temperature and the concentration of ions of hydrogen-like acceptors and donors are to assure all t-defects to be in the charge state (0). It is shown that in such an element it is possible to cool down the metal-semiconductor contact under a negative electric potential and to heat up the opposite contact under a positive potential.

Download Full-text

Low-Frequency Admittance of Capacitor with Working Substance “Insulator–Partially Disordered Semiconductor– Insulator”

Devices and Methods of Measurements ◽

10.21122/2220-9506-2021-12-3-202-210 ◽

2021 ◽

Vol 12 (3) ◽

pp. 202-210

Author(s):

N. A. Poklonski ◽

I. I. Anikeev ◽

S. A. Vyrko

Keyword(s):

Charge State ◽

Crystalline Silicon ◽

Low Frequency ◽

Practical Interest ◽

Structural Defects ◽

Crystal Matrix ◽

Single Electrons ◽

Radiation Resistant ◽

Charge States ◽

State 1

The study of the electrophysical characteristics of crystalline semiconductors with structural defects is of practical interest in the development of radiation-resistant varactors. The capacitance-voltage characteristics of a disordered semiconductor can be used to determine the concentration of point defects in its crystal matrix. The purpose of this work is to calculate the low-frequency admittance of a capacitor with the working substance “insulator–crystalline semiconductor with point t-defects in charge states (−1), (0) and (+1)–insulator”. A layer of a partially disordered semiconductor with a thickness of 150 μm is separated from the metal plates of the capacitor by insulating layers of polyimide with a thickness of 3 μm. The partially disordered semiconductor of the working substance of the capacitor can be, for example, a highly defective crystalline silicon containing point t-defects randomly (Poissonian) distributed over the crystal in charge states (−1), (0), and (+1), between which single electrons migrate in a hopping manner. It is assumed that the electron hops occur only from t-defects in the charge state (−1) to t-defects in the charge state (0) and from t-defects in the charge state (0) to t-defects in the charge state (+1).In this work, for the first time, the averaging of the hopping diffusion coefficients over all probable electron hopping lengths via t-defects in the charge states (−1), (0) and (0), (+1) in the covalent crystal matrix was carried out. For such an element, the low-frequency admittance and phase shift angle between current and voltage as the functions on the voltage applied to the capacitor electrodes were calculated at the t-defect concentration of 3∙1019 cm−3 for temperatures of 250, 300, and 350 K and at temperature of 300 K for the t-defect concentrations of 1∙1019, 3∙1019, and 1∙1020 cm−3.

Download Full-text

Evaluation of the Structure Factor of Cuprite and Bonding Chracterisitcs

Microscopy and Microanalysis ◽

10.1017/s1431927600012150 ◽

1997 ◽

Vol 3 (S2) ◽

pp. 1053-1054

Author(s):

M. Y. Kim ◽

J. M. Zuo ◽

J. C. H. Spence

Keyword(s):

Charge State ◽

Oxygen Deficiency ◽

Copper Oxides ◽

Naturally Occurring ◽

Simple Cubic ◽

Bcc Structure ◽

Structure And Bonding ◽

Charge States ◽

The Relationship ◽

Oxygen Atoms

Cu2O is a semiconductor with a band gap of 2.17eV, and its crystal structure is simple cubic. Oxygen atoms form a bcc structure and each oxygen atom is tetrahedrally coordinated by copper atoms, which makes copper linearly coordinated by two oxygen atoms. The structure of cuprite is interesting because the charge state of Cu and oxygen. The most common charge states of Cu is 2+, however, in cuprite for each oxygen there are two Cu atoms which suggest a 1+ charge state of Cu. Charge density of Cu and oxygen are also interesting because of the high Tc superconductors based on copper and oxygen planes and chains. The superconductivity is believed due to the different charge states of copper and/or oxygen in the Cu-oxygen planes due to the doping or oxygen deficiency. by studying the naturally occurring charge states of Cu in Cu2O and CuO, a better understanding of the relationship between structure and bonding can be achieved for the important copper oxides.

Download Full-text

Formation of different charge states and the charge state fractions of sputtered Ti and Ni

Surface Science Letters ◽

10.1016/0167-2584(86)90930-8 ◽

1986 ◽

Vol 166 (2-3) ◽

pp. A50

Author(s):

H.J. Barth ◽

E. Mühling ◽

W. Eckstein

Keyword(s):

Charge State ◽

Charge States

Download Full-text

Quantifying charge state heterogeneity for proteins with multiple ionizable residues

10.1101/2021.08.31.458420 ◽

2021 ◽

Author(s):

Martin J Fossat ◽

Ammon E Posey ◽

Rohit V Pappu

Keyword(s):

Charge State ◽

Protein Solutions ◽

Solution Ph ◽

Net Charge ◽

Pka Values ◽

Intrinsically Disordered ◽

Conformational Preferences ◽

Charge States ◽

Ionizable Residues ◽

Analyze Data

For proteins with multiple ionizable residues, the canonical assumption is that ionization states of residues are fixed by their intrinsic pKa values. However, several studies have shown that protonation / deprotonation of acidic vs. basic sidechains is realizable even when the solution pH is kept fixed at values that are far away from the intrinsic pKa values. Indeed, protein solutions are best described as ensembles of charge microstates, with each member of the ensemble being a distinct charge microstate defined by differences in charge states for ionizable residues. Accordingly, for a given set of solution conditions, the true partition function is sum over all charge microstates and all the Boltzmann weights of all conformations associated with each of the charge microstates. Here, we leverage the advantages afforded by potentiometric titrations to measure global net charge as a function of pH, independent of considerations of conformational preferences. The systems studied are fragments of proteins with repetitive patterns of Lys and Glu. We analyze the potentiometry data using the recently introduced formalism of the q-canonical ensemble. In this ensemble, charge microstates can be grouped into mesostates. Each mesostate is a collection of microstates of the same net charge. We analyze data for global charge vs. pH to extract mesostate populations as a function of pH. Our findings reveal that the heterogeneity of charge states makes significant contributions to measured charge profiles. This has significant implications for the types of species that are present in solution, even for a fixed pH. Measurements of net charge, decoupled from measurements of conformational equilibria, and analyzed to extract the pH-dependent populations of different mesostates, will be significant for accurate understanding of how charge state heterogeneity contributes to conformational, binding, and phase equilibria of proteins, especially those that are intrinsically disordered.

Download Full-text

THERMAL ACTIVATION ENERGY OF HOPPING ε2-CONDUCTION VIA BORON ATOMS IN WEAKLY COMPENSATED SILICON

Doklady of the National Academy of Sciences of Belarus ◽

10.29235/1561-8323-2018-62-4-406-414 ◽

2018 ◽

Vol 62 (4) ◽

pp. 406-414

Author(s):

Nikolai A. Poklonski ◽

Sergey A. Vyrko ◽

Alexander I. Kovalev

Keyword(s):

Activation Energy ◽

Charge State ◽

Energy Gap ◽

Average Distance ◽

Energy Levels ◽

Band Shift ◽

Impurity Atoms ◽

V Band ◽

Silicon Crystals ◽

Charge States

The insulating side of the concentration insulator–metal phase transition (Mott’s transition) in p-type silicon crystals doped with acceptor (boron atoms) is considered under the conditions of stationary hopping electrical conduction. The boron atoms substitute silicon atoms in the crystal lattice and can be in one of the three charge states (−1, 0, +1), while the compensating impurity (donors) is in the charge state (+1). The distribution of impurity atoms is supposed to be random (Poisson’s distribution). The A0-band is formed from the energy levels of boron atoms in the charge states (0) and (−1), while the A+-band is formed from the energy levels of boron atoms in the charge states (+1) and (0). The decrease in the activation energy ε2 of thermally assisted tunneling transitions (hops) of holes between electrically neutral boron atoms, i. e. boron atoms that are in the charge state (0), is calculated. The ε2 quantity is approximately equal to an energy gap between A0- and A+-bands, i. e. Hubbard’s gap. In the quasi-classical approximation it is shown that the narrowing of the energy gap between A0- and A+-bands occurs due to: (i) the formation of a quasi-continuous band of allowed energy values for v-band holes from excited quantum states of boron atoms in the charge state (0), thus the value of the v-band shift into the band gap is determined by a maximum radius of the hole orbit in a boron atom, which does not exceed the half of the average distance between the nearest impurity atoms, and (ii) the splitting of the ground (non-excited) energy levels of the “molecular” pairs of boron atoms in the charge states (0) into triplet and singlet states of two holes. Calculations of ε2 without any adjustable parameters are quantitatively agree with the known experimental data on p-Si:B.

Download Full-text

Spectroscopy of Transition-Metal-Hydrogen Complexes in Silicon

MRS Proceedings ◽

10.1557/proc-378-341 ◽

1995 ◽

Vol 378 ◽

Cited By ~ 1

Author(s):

Michael Stavola ◽

S.J. Uftring ◽

M.J. Evans ◽

P.M. Williams ◽

G.D. Watkins

Keyword(s):

Electron Paramagnetic Resonance ◽

Electrical Properties ◽

Transition Metal ◽

Charge State ◽

Vibrational Spectroscopy ◽

Structural Information ◽

Paramagnetic Resonance ◽

Charge States ◽

Electron Paramagnetic

AbstractTransition-metal-hydrogen complexes have been introduced into bulk Si samples that contained Pt, Au, or Rh by the indiffusion of hydrogen at 1250°C from H2 gas. The structure and electrical properties of a PtH2 complex in Si have been studied by vibrational spectroscopy and electron paramagnetic resonance (EPR). The PtH2 complex has been found to introduce two levels in the Si bandgap. There is one paramagnetic charge state for which EPR provides detailed structural information and two nonparamagnetic charge states. The hydrogen vibrations of all three charge states of PtH2 have been assigned. In addition to the PtH2 complex, the hydrogen vibrations of several additional complexes in Si samples that contain hydrogen and Pt, Au, or Rh have been identified.

Download Full-text

Manipulation of Charge States of Biopolymer Ions by Atmospheric Pressure Ion/Molecule Reactions Implemented in an Extractive Electrospray Ionization Source

European Journal of Mass Spectrometry ◽

10.1255/ejms.879 ◽

2007 ◽

Vol 13 (4) ◽

pp. 273-279 ◽

Cited By ~ 21

Author(s):

Huanwen Chen ◽

David Touboul ◽

Matthias Conradin Jecklin ◽

Jian Zheng ◽

Mingbiao Luo ◽

...

Keyword(s):

Electrospray Ionization ◽

Charge State ◽

Atmospheric Pressure ◽

Ambient Pressure ◽

Quadrupole Ion Trap ◽

Ionization Source ◽

Ion Molecule Reactions ◽

Multiply Charged ◽

Charge States ◽

Low Charge

A home-made extractive electrospray ionization source is coupled to an linear quadrupole ion trap mass spectrometer to investigate ion/molecule reactions of biopolymers at ambient pressure. Multiply charged biopolymers such as peptides and proteins generated in an electrospray are easily reduced to a low charge state by the atmospheric pressure ion/molecule reactions occurring between the multiply charged ions and a strong basic reagent sprayed in neutral form into the electrospray plume. The charge state of the biopolymer ions can be manipulated by controlling the amount of the basic reagent. The production of biopolymer ions with low charge states results in a substantial improvement of sensitivity and reduced spectral congestion in ESI-MS. This is of importance for biopolymer mixture analysis and could have promising applications in proteomics.

Download Full-text

Excitation of Swift Heavy Ions in Foil Targets. IV. Preequilibrium Energy Losses and Mean Charge States

Australian Journal of Physics ◽

10.1071/ph880681 ◽

1988 ◽

Vol 41 (5) ◽

pp. 681 ◽

Cited By ~ 10

Author(s):

LB Bridwell ◽

HJ Hay ◽

LF Pender ◽

CJ Sofield ◽

PB Treacy

Keyword(s):

Charge State ◽

Charge Exchange ◽

Monte Carlo Analysis ◽

Energy Losses ◽

Ionic Charge ◽

Thin Carbon ◽

Charge State Distributions ◽

Charge States ◽

Mean Charge ◽

Exchange Data

Studies have been made of the approach to energy-loss and charge-state equilibrium of initially pure charge states of ions, transmitted through thin carbon targets. Ions of Li, F and C1 at 3 MeV per AMU were used. Detailed observations were made of outgoing energy losses and charge-state distributions, for outgoing charges equal to those ingoing. A Monte Carlo analysis is made of the charge changing processes, which allows calculation of energy losses due to projectile charge exchange. The residual electronic target-ionisation loss is analysed to predict in-target charge states of the projectile ions. Using these, a comparison is made between the in-target effective charge for target ionisation, and the averaged ionic charge which fits charge-exchange data.

Download Full-text