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calculation of mean energy value of CMB photons for recombination

I am interested in the calculation of the mean energy value of CMB (Cosmic Microwave Background) photons from which the recombination is performed. The subject on French Wikipedia says : "...
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1answer
55 views

Could an ion cannon be in fact a proton beam? [closed]

For a while I have been fascinated with the real science behind some of the most common sci-fi weaponry out there, and I always like to find out which ones make any sense (although we cease ...
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1answer
41 views

Photoelectric effect on charged plate

As far as I know, to observe the photoelectric effect, one has to expose a metal surface to high-energy radiation. But what happens if the surface has a surplus of electrons? What is the energy needed ...
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1answer
69 views

Why does ionization energy increase with period for transition metals but not for the s and p blocks?

I noticed this the other day, and rather than go hunt in some atomic physics book I thought I'd post it here where the answer will hopefully be more useful to the wider internets. I was looking at ...
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1answer
48 views

Why work function is not identical to first ionization energy?

From Wikipedia: The ionization energy (IE) is qualitatively defined as the amount of energy required to remove the most loosely bound electron of an isolated gaseous atom to form a cation. ...
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1answer
51 views

Which electron is first ionized $n=2,\ell=1, m=?$ [closed]

Eletrons in atoms are described by n,l, m, s quantum numbers? For noble gas 1s2 2s2 2p6 which is the first electron that will be ionized n=2, l=1, m=?, s = ?
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30 views

Could two electrolasers be used as a cutting tool for non-conductive materials like rock?

An electrolaser is an ionizing laser that turns the air molecules in its path to a conducting plasma. There have already been experiments with electrolasers as thunderpoles. You can also inject a ...
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0answers
59 views

How much of the Solar convection zone is completely ionized?

I was reading about the energy transportation in stars here, and I found this: "The outer portion of solar mass stars is cool enough that hydrogen is neutral and thus opaque to ultraviolet photons, so ...
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40 views

Could there be ways to form hypergiant stars, quasars or supermassive black holes at the beginning of the Dark Ages?

Original title: Heat loss in collapsing parcels of gas or weak plasma at the beginning (not the end) of the cosmological dark ages Star formation from collapsing parcels of primordial gas in the late ...
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19 views

Why spurious pulses are likely in partial discharges?

My notes The gas multiplication in the proportional counters is based on the secondary ionization created in collisions between electrons and neutral gas molecules, resulting in some visible ...
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1answer
2k views

What's the difference between the work function and ionisation energy?

In a particular textbook, the work function of a metal (in the context of the photoelectric effect) is defined as: the minimum amount of energy necessary to remove a free electron from the surface ...
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3answers
79 views

Is there an example of a situation where you need a continuous spectrum?

If you had a hydrogen atom you could say that you want to be able to ionize them. But if you then add the potential due to the earth, e.g. $$V=\frac{-Gm_eM_\oplus}{\sqrt{(x_e-x_\oplus)^2+(y_e-y_\oplus)...
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58 views

Why can xenon gas stay ionised after the “trigger voltage” is removed?

From my understanding of a Xenon flash circuit, a storage capacitor and a trigger capacitor are charged up to about 240V (both with similar RC values, but less capacitance is needed for the trigger ...
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1answer
82 views

If energy is required to add the electron to gaseous atom then why further energy is required to remove it?

If energy is required to add the electron to gaseous atom (electron affinity - in case of noble gases) then why is further energy (ionization energy) required to remove it? The reason for ionization ...
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1answer
110 views

How does a high voltage produce ions

I was reading about gas discharge tubes and it said that when a high voltage is applied between the cathode and anode, electrons get pulled off the gas atoms. My question is how does this happen ...
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1answer
283 views

How is an atom ionized by electron impact?

Can someone walk me through in detail what happens when an atom is ionized by colliding with an electron? I would prefer a solid example so I can understand it more concretely. What I think: The ...
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1answer
46 views

What would you do to measure wind speed below 50m?

Is there a radiation spectrum that could be used near the surface of the earth to fluoresce air enough to see the currents? Is there a complimentary CCD that can image that spectrum? I am looking for ...
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3answers
96 views

Can we create plasma with other things except gas?

In my school book its written on how plasma is created and it is said that we can create plasma by ionizing a gas but i have heard that plasma can be created even from liquids like water and also from ...
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4answers
300 views

Why aren't we affected by radium?

1)We have radium clocks, watches, wrist bands and many things which glow because of radium but we know that radium is radioactive so why isn't it harmfull for us when in bands, watches etc. 2)Does it ...
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110 views

Hydrogen atom Ionization by Magnetic Field [closed]

The source of a magnetic field (it could be a magnetic dipole) is moving at relativistic speed. This magnetic field encounters a hydrogen atom at rest with respect to the source. Will this encounter ...
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1answer
307 views

Do magnetic fields cause ionisation of gases?

I am doing my final year engineering project on Magnetic Field Assisted Combustion and was curious to see what people thought about it. Companies sell rare earth magnetic arrangements to be attached ...
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1answer
62 views

What was the significance of the ionization caused by the Population III stars?

I am reading that the ultraviolet light that radiated from the first stars would ionize the surrounding gas and apparently, all of the matter in the universe would eventually become ionized. So, ...
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1answer
2k views

Can a UV LED cause air ionization?

I am thinking of the high power LEDs at around 250nm wavelength and an output power of some 30mW optical, in continuous mode either divergent beam or focused.
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1answer
269 views

DFT Calculations, Atomic Ionization Potentials — Which Exchange-Correlation Functional to Use, to Preserve Koopmans' Theorem?

I have a program which can perform density-functional calculations for atoms, given a density functional. Of course the simplest form of exchange potential to use is one relevant for a uniform ...
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1answer
2k views

Difference between a hydrogen ion and a proton

I've run into a bit of a problem on this weeks coursework. A proton and an electron initially at rest combine to form hydrogen. Find the wavelength of the emitted photon? So, as far as I can ...
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27 views

Proton energy distribution after Si layer

I've been using SRIM to get an approximation of the energy distribution that a beam of monoenergetic incident ions will have after a thin layer of silicon. However, for my purposes it would be better ...
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2answers
94 views

If an atom is positively ionized, can is gain electrons if you emit photons at it?

I read somewhere that electrons and light are just electromagnetic radiation and are basically the same thing, does this mean that if you emit photons at an atom it will gain electrons?
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3answers
382 views

Ionization by heating

I would like to ask what happens if an atom exposed to a very high temperature - say millions of degrees (Kelvin). Can we use heating to separate electrons from their nucleus? And what happens to the ...
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1answer
33 views

Ionization of Electrons Intensity Relationship

Why can't light eject electrons out of atoms (ie. do ionization radiation)? Although the energy of light photons are low (more or less 2 eV), can't 5 photons consecutively hit the electron and make it ...
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2answers
355 views

Why does hydrogen give up its electron to a platinum catalyst?

All descriptions of a Hydrogen fueled fuel cell (such as this one) Start with $H_2$ giving up its electrons to a platinum coated anode. Then the $H^+$ ions (protons really) travel through the ...
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1answer
223 views

How is ionization explained in Quantum Mechanics?

I remember in my highschool chemistry classes, they taught that an atom can be ionized when it loses a valence electron and becomes positively charged. In quantum mechanics, if electrons aren't really ...
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61 views

Ion-neutralization processes and its energies

Ionization energies/Electron affinities are well mapped. I wonder about opposite processes... I imagine for anion the necessary energy will be equal to the electron affinity (energy released when ...
2
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2answers
143 views

Can a laser be designed to ionize muonic atoms so as to prevent a-sticking?

Muon catalyzed fusion is currently little more than a lab curiosity today in part because of how many hydrogen nuclei can be fused before the muon is carried away by an alpha particle. Deuterium+...
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1answer
441 views

Hydrogen ionization energy [closed]

Proton and electron have a distance equal to the Bohr radius apart in the hydrogen atom. Knowing this, what's the ionization energy of the atom? So we know $U = -kq^2/a_B$, but this is potential ...
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2answers
89 views

x-ray in oil droplets experment

In oil droplet experiment, x-ray makes the air molecules negatively charged. How does that work? X-ray carries high energy and ionizes air, doesn't that make air positively charged?
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1answer
259 views

What happens to gas molecules after ionization?

I know that gas molecules conduct electricity after they get ionized but what will happen if we keep increasing the voltage even after ionization? Will it explode? If it will then how much energy ...
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1answer
345 views

What happens when you give excess energy to an atom?

So this is my question: An electron in a hydrogen atom in its ground state absorbs energy equal to the ionisation energy of $Li^{2+}$. The wavelength of the emitted electron is? I started off by ...
2
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1answer
92 views

Ionization Energy and Bohr

I was having problems with ionization energy - but all it is is the energy required to remove first electron that pops off right? In the case of Bohr's atom, there's only one electron, so it's that ...