scholarly journals The scattering of hydrogen positive rays, and the existence of a powerful field of force in the hydrogen molecule

1922 ◽  
Vol 102 (715) ◽  
pp. 197-209 ◽  
Keyword(s):  
Electric Fields ◽  
General Scheme ◽  
Hydrogen Gas ◽  
Theoretical Interpretation ◽  
Scattering Medium ◽  
Hydrogen Atoms ◽  
Hydrogen Molecules ◽  
Nuclear Particle ◽  
Positively Charged ◽  
Made In

In view of the extremely important results obtained by Sir E. Rutherford and others from a study of the scattering of α -rays, it seemed worth while to investigate the scattering of particles moving with smaller velocities such as occur in the positive rays. The most interesting, because the simplest, are the rays of positively charged hydrogen atoms, which presumably consist simply of a nuclear particle, or proton. The experiments described in this paper were made in some cases with these rays, in others with the positively charged hydrogen molecules, systems consisting of two protons and one electron. The scattering medium was in all cases hydrogen gas. This was chosen largely for convenience, as the experimental arrangement is considerably simplified if the same gas is used to produce the rays and to scatter them, and also because, with the exception of helium, the molecule of hydrogen is the simplest known, and there seemed more hope of obtaining results which could be given a definite theoretical interpretation. The general scheme of experiment was to produce the rays in a discharge tube, analyse them by magnetic and electric fields in the ordinary way, cut off all except those of the kind required by a slotted diaphragm, pass the remainder through a chamber containing the scattering gas, and receive them in a Faraday cylinder arranged behind a slit of variable width. The experiment consisted in finding how the charge received by the Faraday cylinder varied with the width of the slit, when this was made wider than the geometrical “shadow” of the slot in the diaphragm. Any rays lying outside this “shadow” must have been scattered.

Photoinduzierte Stoßprozesse metastabiler Wasserstoffatome mit H2 im Energiebereich von 0,05 — 0,47 eV

1969 ◽  
Vol 24 (4) ◽  
pp. 587-596 ◽  
Author(s):  
F. J. Comes ◽  
U. Wenning
Keyword(s):  
Electric Fields ◽  
Cross Sections ◽  
Collision Cross Section ◽  
Translational Energy ◽  
Selective Absorption ◽  
Hydrogen Atoms ◽  
Excited Atoms ◽  
Hydrogen Molecules ◽  
Vibrational Levels ◽  
The Difference

Abstract Molecular hydrogen was excited by selective absorption of ultraviolet radiation of appropriate wavelength into the vibrational levels ν′ 3, 4, and 5 of the electronic D (1IIu)-state. For the radiation bandwidth chosen the molecule was only formed in the rotational levels J = 1 and 2 of the R-branch. The excited molecules decay by predissociation into two hydrogen atoms of translational energy which is equal to one half of the difference between the excitation and dissociation energies. One of the atoms is formed in its first excited state. The formation of the excited species can be proven by its fluorescence (Lymanα-radiation). As a result the measurements show, that the excited atoms are all in the metastable 2S-state and not in the short-lived 2P -state. Without electric fields these metastable atom s loose their excitation energy in collisions with the surrounding hydrogen molecules. One part (a) follows an induced transition to the electronic ground state by the emission of Lyα-radiation (1216 Å), the other part (b) is transformed to products or undergoes an energy transfer process without emitting Lyα-radiation. If a quenching field is applied spontaneous emission will compete with collisional deactivation, which allows the deactivation cross sections to be calculated. These cross sections are between 50 and 100 Å2 (a) and about 50 Å2 in case (b). In case (a) the collision cross section increases with the velocity of the particles whereas in case (b) a constant value was found.

scholarly journals The electric fields of South African thunderstorms

1927 ◽  
Vol 114 (767) ◽  
pp. 229-243 ◽  
Keyword(s):  
South African ◽  
Electric Fields ◽  
Negative Charge ◽  
Reverse Current ◽  
Positive Polarity ◽  
The Earth ◽  
Fine Weather ◽  
Lightning Discharges ◽  
Positively Charged ◽  
Made In

The quantitative study of the electrical changes taking place in thunderstorms was initiated and has been developed by Prof. C. T. R. Wilson in two important papers. Measurements of the electric fields due to charged clouds and of the field changes associated with lightning discharges have led him to put forward certain views according to which the thunderstorm is an important factor in the production and maintenance of several electro-meteorological phenomena with which it has not previously been considered connected. Chief amongst these is the negative charge on the surface of the earth, for the replenishment of which the views of Wilson require a certain preponderance of thunderclouds of positive polarity, i.e ., positively charged above and negatively charged below, over clouds of negative polarity, the ionisation currents between the bases of the clouds of the former type and the ground serving to maintain the earth’s charge at a steady value in spite of the reverse current flowing in regions of fine weather. It is necessary, in order to test this theory, that observations be made in different parts of the world to examine whether the required preponderance of clouds of positive polarity exist. For this purpose South Africa, which contributes largely to the world’s supply of thunderstorms, is very suitable.

The Curious Incident of the Dog in the Airship

2013 ◽  
Author(s):  
Lars Öhrström
Keyword(s):  
New York ◽  
Hydrogen Gas ◽  
Department Of Energy ◽  
Hydrogen Atoms ◽  
Energy Applications ◽  
The Us ◽  
Single Chemical ◽  
History Of ◽  
To Come ◽  
Positively Charged

Joseph Späh had to feed his dog; nothing strange about that. The problem was that Ulla, an Alsatian, was mostly confined to the freight room—off limits to passengers. Had everything gone according to schedule, this would not have been an issue either, except for gruff remarks from crewmen not appreciating the needs of this canine friend and co-worker in Späh’s stage act. But this flight did not go according to plan, and Späh’s frequent visits to the rear of the Hindenburg would give him problems in the years to come. The US Department of Energy, and its counterparts in Europe and Japan, are currently spending billions on developing the use of hydrogen for future energy applications—for example, as a fuel for cars and buses. The main advantage is the clean combustion of this fuel: two molecules of hydrogen gas will combine with one molecule of oxygen and give two molecules of water. The future belongs, perhaps, to the ‘hydrogen economy’, but unfortunately for its proponents, the popular history of hydrogen as a fuel is bound up with the tragedy of the Hindenburg. We will get back to Joseph Späh’s poor dog in a while, but for now ponder the fact that over the dog, and above everyone else aboard the comfortable and luxurious Hindenburg , there were huge ‘bags’ filled with hydrogen—the lightest of all the elements, with only one proton and one electron. It has the lowest density of any gas, and is formed by two hydrogen atoms combined together via a single chemical bond, made by sharing the two negatively charged electrons between the two positively charged nuclei. This H2 gas had carried the world’s largest airship from Frankfurt to Lakehurst outside New York, and before that on successful tours all over the globe during the preceding year. These days, we tend to wonder how people could even contemplate the idea of travelling around in what can be described as a flying bomb.

Investigation of the Hydrogen Transport Processes in Crystalline Silicon of n-Type Conductivity

2007 ◽  
Vol 131-133 ◽  
pp. 425-430 ◽  
Author(s):  
Anis M. Saad ◽  
Oleg Velichko ◽  
Yu P. Shaman ◽  
Adam Barcz ◽  
Andrzej Misiuk ◽  
...  
Keyword(s):  
Hydrogen Concentration ◽  
Room Temperature ◽  
Crystalline Silicon ◽  
Transport Processes ◽  
Concentration Profiles ◽  
Hydrogen Transport ◽  
Hydrogen Atoms ◽  
Near Surface ◽  
Type Conductivity ◽  
Hydrogen Molecules

The silicon substrates were hydrogenated at approximately room temperature and hydrogen concentration profiles vs. depth have been measured by SIMS. Czochralski grown (CZ) wafers, both n- and p-type conductivity, were used in the experiments under consideration. For analysis of hydrogen transport processes and quasichemical reactions the model of hydrogen atoms diffusion and quasichemical reactions is proposed and the set of equations is obtained. The developed model takes into account the formation of bound hydrogen in the near surface region, hydrogen transport as a result of diffusion of hydrogen molecules 2 H , diffusion of metastable complexes * 2 H and diffusion of nonequilibrium hydrogen atoms. Interaction of 2 H with oxygen atoms and formation of immobile complexes “oxygen atom - hydrogen molecule” (O - H2 ) is also taken into account to explain the hydrogen concentration profiles in the substrates of n-type conductivity. The computer simulation based on the proposed equations has shown a good agreement of the calculated hydrogen profiles with the experimental data and has allowed receiving a value of the hydrogen molecules diffusivity at room temperature.

THE BAND GAP ESTIMATION OF ZINC MANGANESE PHOSPHATE GLASSES

2008 ◽  
Vol 22 (12) ◽  
pp. 1265-1272 ◽  
Author(s):  
S. A. SIDDIQI ◽  
M. A. GHAURI ◽  
M. J. S. BAIG
Keyword(s):  
Electric Fields ◽  
Spectral Dependence ◽  
Transport Mechanism ◽  
Phosphate Glasses ◽  
Band Gaps ◽  
Spectral Energy ◽  
Charge Transport Mechanism ◽  
Optical Band Gaps ◽  
Manganese Phosphate ◽  
Made In

Zinc manganese phosphate glasses ( ZnO - MnO - P 2 O 5) of different compositions are synthesized. The optical band gaps are measured in the UV-VIS region. Photoconduction measurements are also made in the spectral energy range 1.5–6.2 eV. At various applied electric fields, the values of the energy band gaps have been deduced from the spectral dependence curves. Furthermore, the band gaps at zero applied voltage were also obtained for different compositions. The charge transport mechanism in these glasses is studied under the Mott's model.

scholarly journals Theoretical Study on the Mechanism of Hydrogen Donation and Transfer for Hydrogen-Donor Solvents during Direct Coal Liquefaction

Catalysts ◽  
2018 ◽  
Vol 8 (12) ◽  
pp. 648 ◽  
Author(s):  
Haigang Hao ◽  
Tong Chang ◽  
Linxia Cui ◽  
Ruiqing Sun ◽  
Rui Gao
Keyword(s):  
Density Functional ◽  
Hydrogen Gas ◽  
Hydrogen Donor ◽  
Coal Liquefaction ◽  
Hydrogen Atoms ◽  
Functional Theory ◽  
Donor Solvent ◽  
National Energy Security ◽  
Liquefaction Process ◽  
Direct Coal Liquefaction

As a country that is poor in petroleum yet rich in coal, it is significant for China to develop direct coal liquefaction (DCL) technology to relieve the pressure from petroleum shortages to guarantee national energy security. To improve the efficiency of the direct coal liquefaction process, scientists and researchers have made great contributions to studying and developing highly efficient hydrogen donor (H-donor) solvents. Nevertheless, the details of hydrogen donation and the transfer pathways of H-donor solvents are still unclear. The present work examined hydrogen donation and transfer pathways using a model H-donor solvent, tetralin, by density functional theory (DFT) calculation. The reaction condition and state of the solvent (gas or liquid) were considered, and the specific elementary reaction routes for hydrogen donation and transfer were calculated. In the DCL process, the dominant hydrogen donation mechanism was the concerted mechanism. The sequence of tetralin donating hydrogen atoms was α-H (C1–H) > δ-H (C4–H) > β-H (C2–H) > γ-H (C3–H). Compared to methyl, it was relatively hard for benzyl to obtain the first hydrogen atom from tetralin, while it was relatively easy to obtain the second and third hydrogen atoms from tetralin. Comparatively, it was easier for coal radicals to capture hydrogen atoms from the H-donor solvent than to obtain hydrogen atoms from hydrogen gas.

Melt Quality Assessment

2019 ◽  
Author(s):  
Derya Dispinar
Keyword(s):  
Aluminum Oxide ◽  
Die Casting ◽  
Liquid Aluminum ◽  
Hydrogen Gas ◽  
Optimized Design ◽  
Hydrogen Atoms ◽  
Reduced Pressure ◽  
Cast Part ◽  
Crystalline Oxide ◽  
Pressure Die Casting

It is well known that the reaction of liquid aluminum with the moisture in the environment results in two products: aluminum oxide and hydrogen gas that dissolves in aluminum. Both of these products are considered to be detrimental to the properties of aluminum alloys. Therefore, test equipment has been developed to check the levels of these defects in the melt. Many of these involve expensive and consumable tools. In addition, an experienced personnel may be required to interpret the results. Nonetheless, aluminum oxide is harmless as long as it remains on the surface. The problem begins when this oxide is entrained into the liquid aluminum such as turbulence during transfer or mold filling in a non-optimized design. This can only happen by folding of the oxide. During this action, rough surface of the oxides comes in contact to form no bonds. These defects are known as bifilms that have certain characteristics. First, they act as cracks in the cast parts since they are oxides. It is important to note that aluminum oxide has thin amorphous oxide (known as young oxides) and thick crystalline oxide (γ-Al2O3) that may be formed in a casting operation. Second, almost zero force is required to open these bifilms due to the unbonded folded oxide skins. Thus, these defects can easily form porosity by unravelling during solidification shrinkage. On the other hand, the formation of porosity by hydrogen is practically impossible. Theoretically, hydrogen has high solubility in the liquid but it has significantly low solubility in solid aluminum. Thus, it is suspected that hydrogen is rejected from the solidification front to form hydrogen gas and porosity. However, the hydrogen atom has the smallest atomic radii and high diffusibility. Therefore, segregation of hydrogen in front of the growing solid is difficult. In addition, the energy required for hydrogen atoms to segregate and form hydrogen gas molecule is around 30,000 atm. Under these conditions, porosity formation by hydrogen is not likely to be achieved. Hydrogen probably stays in a supersaturated state or diffuses homogeneously through the cast part. The effect of hydrogen can only be seen when it can diffuse into the unbonded gap between the bifilms to open them up to aid the unravelling of bifilms to form porosity. This phenomenon can be easily detected by a very simple test called reduced pressure test. When a sample is solidified under vacuum, the bifilms start to open up. Since all porosity is formed by bifilms, the cross section of the sample solidified under vacuum can be analyzed by means of image analysis software. The sum of maximum length of pores can be measured as an indication of melt quality. Since bifilms are the most detrimental defects, this value is called “bifilm index” given in millimetres, which makes this test the only test that can quantify aluminum melt quality in such detail including both the effects of bifilms and hydrogen together. Several Al-Si alloys were used at various conditions: degassing with lance, ceramic diffusers, and graphite rotary has been compared. Gravity sand casting, die casting, and low-pressure die casting methods were evaluated. The effect of grain refiners and modifiers was studied. And the evolution of the bifilm index has been presented.

scholarly journals Generation of Charged Ti Nanoparticles and Their Deposition Behavior with a Substrate Bias during RF Magnetron Sputtering

Coatings ◽  
2020 ◽  
Vol 10 (5) ◽  
pp. 443
Author(s):  
Ji-Hye Kwon ◽  
Du-Yun Kim ◽  
Nong-Moon Hwang
Keyword(s):  
Electron Microscopy ◽  
Vapor Deposition ◽  
Physical Vapor Deposition ◽  
Film Growth ◽  
Film Deposition ◽  
Calculated Density ◽  
X Ray ◽  
Positively Charged ◽  
Made In ◽  
Ti Films

This study is based on the film growth by non-classical crystallization, where charged nanoparticles (NPs) are the building block of film deposition. Extensive studies about the generation of charged NPs and their contribution to film deposition have been made in the chemical vapor deposition (CVD) process. However, only a few studies have been made in the physical vapor deposition (PVD) process. Here, the possibility for Ti films to grow by charged Ti NPs was studied during radio frequency (RF) sputtering using Ti target. After the generation of charged Ti NPs was confirmed, their influence on the film quality was investigated. Charged Ti NPs were captured on amorphous carbon membranes with the electric bias of −70 V, 0 V, +5 V, +15 V and +30 V and examined by transmission electron microscopy (TEM). The number density of the Ti NPs decreased with increasing positive bias, which showed that some of Ti NPs were positively charged and repelled by the positively biased TEM membrane. Ti films were deposited on Si substrates with the bias of −70 V, 0 V and +30 V and analyzed by TEM, field-emission scanning electron microscopy (FESEM), X-ray diffraction (XRD) and X-ray reflectivity (XRR). The film deposited at −70 V had the highest thickness of 180 nm, calculated density of 4.974 g/cm3 and crystallinity, whereas the film deposited at +30 V had the lowest thickness of 92 nm, calculated density of 3.499 g/cm3 and crystallinity. This was attributed to the attraction of positively charged Ti NPs to the substrate at −70 V and to the landing of only small-sized neutral Ti NPs on the substrate at +30 V. These results indicate that the control of charged NPs is necessary to obtain a high quality thin film at room temperature.

A New Electrically Reversible Depassivation/Passivation Mechanism in Polycrystalline Silicon

1996 ◽  
Vol 424 ◽  
Author(s):  
Vyshnavi Suntharalingam ◽  
Stephen J. Fonash
Keyword(s):  
Electric Fields ◽  
Polycrystalline Silicon ◽  
Solid Phase ◽  
Hydrogen Release ◽  
Temperature Bias ◽  
Polysilicon Films ◽  
The Stability ◽  
Quartz Substrates ◽  
Hydrogenated Amorphous ◽  
Positively Charged

AbstractAn electrically reversible depassivation/passivation phenomenon, recently found for hydrogen passivated polysilicon [1] is further explored in this report. This reversible effect is seen in both ECR and RE hydrogen passivated n-channel thin film transistors (TFTs) but is not seen in the corresponding hydrogen passivated pchannel TFrs, nor is it seen in either n- or p-channel TETs before hydrogenation. This phenomenon has been observed when room temperature bias stressing TFTs fabricated on solid phase or laser crystallized polysilicon films on quartz substrates [1]. A model involving hydrogen release or capture at defects, positively charged hydrogen motion in device electric fields, and subsequent hydrogen capture at other defects has been proposed. This phenomenon has significant implications for polycrystalline silicon TFT’ design and operation. By extension, it also offers significant insight into the stability problems of hydrogenated amorphous silicon.

scholarly journals The chemical constant of hydrogen vapour and the entropy of crystalline hydrogen

1931 ◽  
Vol 130 (813) ◽  
pp. 367-379 ◽  
Keyword(s):  
Vapour Pressure ◽  
Low Temperatures ◽  
Hydrogen Gas ◽  
Para Hydrogen ◽  
Bose Statistics ◽  
Hydrogen Molecules ◽  
Quantum Numbers ◽  
A Value ◽  
Classical Statistics ◽  
Chemical Constant

In a paper called "The Chemical constant of Hydrogen Vapour and the failure of Nernst's Heat Theorem," R. H. Fowler has investigated the vapour pressure of hydrogen crystals at low temperature; taking account of the existence of two sorts of hydrogen molecules, namely, ortho-hydrogen with even rotational quantum numbers and para-hydrogen with odd rotational quantum numbers, which retain their individuality over long periods at very low temperatures. By the use of the classical statistics, he was able to show that at very low temperatures hydrogen, as obtained by cooling hydrogen gas from ordinary temperatures, ought to have very nearly the experimentally observed chemical constant. Since the theory of the specific heat of hydrogen yielded correct values at low temperatures, it followed that at ordinary temperatures also his theory would yield a correct value for the chemical constant. Finally from the form of the partition function for hydrogen gas, Fowler attempted to obtain inferences concerning the validity of Nernst's heat theorem. By the use of the classical statistics fairly accurate results were obtained. But we shall find that when we make use of the Einstein-Bose statistics-the correct statistics for an assembly of hydrogen moleclues-a result will be obtained for the vapour pressure of hydrogen crystals at low temperatures which will furnish a value for the chemical constant of hydrogen in even closer agreement with experiment than Fowler's result.

Sign in / Sign up

Export Citation Format

Share Document