Atom Definition and 999 Threads

From Wikipedia and other sources that I am reading, a laser detuning can excite an atom. However, for an atom to become excited its energy must be equal to the energy difference of two states. So how can laser detuning still excite an atom? The frequency from the laser would of course be near...

My attempted solutions was, for example let's say we have 4 atoms, and if i ask the oracle about any two atoms that are connected by edge, i can narrow done some possibilities to two atoms. I'm still not sure where i am going with my solution, but if any of you can think this through and come up...

Hello, I have a little problem understanding the quantum mechanics of a hydrogen atom. Im troubled with the following question: before i measure the state of a (simplified: without fine-, hyperfinestructure) hydrogen atom, which is the right probability density of finding the electron? is it...

The Bohr atom gave the answer to the spectrum of the hydrogen atom. But the spectra of stars contains many absorption (and sometimes emission) lines, corresponding to most atoms (up to iron, I believe). And atmospheric absorption is also due to absorption of some molecules, such as water...

Considering the quantum mechanical model for an atom, what exactly happens when two atoms (say, two Ca2+ ions in a Brownian motion) collide with each other? As I know, this collision is not like a regular elastic or inelastic collision between two macroscopic objects. Is it mainly due to the...

I've been adding some renderings I did of the M87 black hole on a different thread and was asked to elaborate on the source of this technique which was investigating images of the shadow of an atom. You can look up the original experiment on Google, as well as observe the final image. The...

I was studying about atomic masses and realized that even if we say that the atomic mass unit corresponds to 1/12 of the mass of a carbon atom. why is it that even particular isotopes of elements have atomic mass in decimal values. 1/12 of a carbon atoms mass should equal to the mass of a...

(In my last thread) Mentor Dale said: " An atom in the ground state can absorb energy from the environment including thermal radiation. Once it has done so it will be excited and will no longer be in the ground state. An excited atom can radiate and go to a lower energy state, but an atom in the...

According to textbooks, an atom in ground state doesn't radiate. Yet I got some other idea after reading Wu Ta-you's theoretical physics book. I hold the viewpoint that the atom does radiate, and at the same time it absorbs energy from heat radiation in its environment. The energy it radiates...

Homework Statement Homework Equations VD= -1/(8m2c2) [pi,[pi,Vc(r)]] VC(r) = -Ze2/r Energy shift Δ = <nlm|VD|nlm> The Attempt at a Solution I can't figure out how to evaluate the expectation values that result from the Δ equation. When I do out the commutator, I get p2V-2pVp+Vp2. This...

I am learning for my exam in particle physics. One topic is statistical physics. There I ran into this question: Consider an atom at the surface of the Sun, where the temperature is 6000 K. The atom can exist in only 2 states. The ground state is an s state and the excited state at 1.25 eV is a...

We could have a copper wire at 10,000 V above a copper plate at 0V. At the end of the wire, one atom of copper. Beneath it: one atom of copper. What is the difference between the two atoms because of this voltage difference? Conventionally the current flows from positive to negative. But...

Hi, I'm having trouble understanding angular moment of the one electron hydrogen atom. Solving Schrodinger equation on a referece system (say S) I get the energy eigenstates. They depend on three quantum numbers, n, l, m \frac{-ħ}{2 m}\nabla^{2} \Psi - \frac{e^{2}}{4 \pi \epsilon r} \Psi =...

Homework Statement Determined wave function in a hydrogen atom. ## Ψ(r,θ,Φ) = A(x+iy)e^{ \frac{-r}{2a_0}}## << find A by normalization Answer of a question in my book is ## A = -\frac{1}{a_0 \sqrt{8 \pi}} (\frac{1}{2a_0})^{3/2} ## Homework Equations ## \int Ψ^*(r,θ,Φ)Ψ(r,θ,Φ) d^3r = \int \int...

What is the probability of an electron being found outside the atom it belongs to? Is it zero or nonzero?

Hello. I have asked Andrew Truscott of the Australian National University on why do lasers not manifest photon bunching like incoherent light does and BEC not manifest any atom bunching. His e-mail reply contains an answer that is a it confusing to me. Can you explain it to me please...

I've noticed that in the Shell Model of the nucleus, the order of the energy levels is 1s, 1p3/2, 1p1/2, etc. While in the atomic energy levels it goes 1S 2S 2P, ... But they still take the same amount of particles for each level in both the atomic and nucleus. Am I missing something here? Or...

Hi How can I define atomic positions of buckled silicene? lattice vectors are a_1=a/2(sqrt(3),-1,0) a_2=a/2(sqrt(3),1,0)

I don't really know where my brain is taking me on this one. I was wondering a couple things.. You set up everything for a Slit Experiment. You shoot an atom and observed it before the slit, then somehow collected the particle. It loops back and shoots it out again, this time with the particle...

Can anny body tell me how do I find the average number of photons in an atom at a given temprature for say lead.

Homework Statement If n=1 is taken to be the reference of the potential energy, what will be the kinetic and potential energy in second excited state of Li2+? Homework Equations E=-13.6z^2/n^2 The Attempt at a Solution I know KE is independent of reference point, so from the formula above...

Homework Statement We are investigating hydrogen in a plasma with the temperature 4500 ºC. Calculate the probability per atom and second for stimulated emission from 2p to 1s if the lifetime of 2p is 1.6 ns Homework Equations Planks radiation law: ##\rho (f) = \frac{8* \pi...

In a coordinate bond, why H^+ atom don't get the negative charge? as an example [NH4]^+ If we split [NH4]^+, we get NH3 + H^+. In NH3, N and 3H atoms have completed their octet and H^+ accepts the lone pair of electrons from the N, As we know H^+ has no any electrons but a proton. If it receives...

The nucleus of the H atom is neutral when it has two electrons and one proton (when forming a covalent bond) or it has one electron and one proton.

The Atom of Helium is doubly excited in 2p2 1D Can someone explain to me how these energy symbols work? I have a problem with what the 1D means specifically. I know 2p2 means two electrons in the 2p state. The 1 in 1D could be referring to electron being in a singleton, but I don't understand...

Homework Statement How to calculate the maximum charge of an atom or a molecule? As we know the equivalent weight = atomic weight / maximum charge Al, Ca and O2The Attempt at a Solution Al, E = 27/3 = 9 Ca, E = 40/2 = 20 O2, E = 16/2 = 8 I see on the books that the charges of Al, Ca and O2 are...

Homework Statement We are investigating hydrogen in a plasma with the temperature 4500 ºC. Calculate the probability per atom and second for stimulated emission from 2p to 1s if the lifetime of 2p is 1.6 ns Homework Equations ##A=\frac{1}{\Sigma \tau}## $$A_{2,1} = \frac{8*\pi *h *...

Homework Statement 12 amu and 1.9924 X 10^-23g express the mass of an atom of C? Homework EquationsThe Attempt at a Solution Do 12 amu and 1.9924 X 10^-23g express the mass of an atom of C? As I know, 6.023 X 10^23 atoms of C weighs 12 g, 1 atom of C weighs 1 X 12 / 6.023 X 10^23 = 12 amu...

There are 118 elements known to man, and some scientists like Feynman think that element 137 might be the end of the Periodic Table. Isn't that oddly specific? To me, it feels like it is completely random and of no significance. What is going on here? Is there a constant that relates to this...

Does molar mass include an atomic weight for single atom and molecular weight for molecules?

My guess is the number is huge,but I don't know what transformations from the hip Iwould use to figure this out.

Consider the pairing term in Weizsäcker formula. Here https://en.wikipedia.org/wiki/Semi-empirical_mass_formula#Pairing_term it is claimed that: I don't understand how Pauli exclusion principle should be the cause of this. This term comes from spin-spin interaction (or "coupling"), but I do not...

Hello all, I have a question. Consider an electron in a shell of an atom has energy as 1.0ev and in the next shell it energy should be 2.7eV and the further next level energy is let's say 3.1eV. Means an energy gap of 1.7eV is their between first and second level and an energy gap o 2.1 eV is...

Homework Statement Real atomic nuclei are not point charges, but can be approximated as a spherical distribution with radius ##R##, giving the potential $$ \phi(r) = \begin{cases} \frac{Ze}{R}(\frac{3}{2}-\frac{1}{2}\frac{r^2}{R^2}) &\quad r<R\\ \frac{Ze}{r} &\quad r>R \\...

Homework Statement Exact spin symmetry in the Dirac equation occurs when there is both a scalar and a vector potential, and they are equal to each other. What physical effect is absent in this case, that does exist in the Dirac solution for the hydrogen atom (vector potential = Coulomb and...

Does anybody know who first drew (not just described but actually drew, even roughly) a model of the atom like the one below, and when: I'd appreciate it if anybody can point me to an evidence.

I need to calculate the energy of the ground state of a helium athom with the variational method using the wave function: $$\psi_{Z_e}(r_1,r_2)=u_{1s,Z_e}(r1)u_{1s, Z_e}(r2)=\frac{1}{\pi}\biggr(\frac{Z_e}{a_0}\biggr)^3e^{-\frac{Z_e(r_1+r_2)}{a_0}}$$ with ##Z_e## the effective charge considered...

Homework Statement Assume that Planck's constant is not actually constant, but is a slowly varying function of time, $$\hbar \rightarrow \hbar (t)$$ with $$\hbar (t) = \hbar_0 e^{- \lambda t}$$ Where ##\hbar_0## is the value of ##\hbar## at ##t = 0##. Consider the Hydrogen atom in this case...

I shall calculate the 2p → 1s transition energies for hydrogen, deuterium (one proton plus one neutron in the nucleus), and positronium (bound state of an electron and a positron). My problem with this exercise is that I couldn't find a formula to calculate the transition energies. Can someone...

Suppose you have an experiment that measures the property of an atom as a whole, maybe you can put it through a double-slit or measure its spin, whatever. Presumably that will collapse the wavefunction that you used to describe the atom in that experiment. Would this entail that in the process...

Which one is correct below 1. a single molecule of H2O 2. a single atom of H2O (if this one is correct then what does it mean?)

Atoms make up all the material stuff around us, but most of an atom is empty space. The nucleus at the centre of an atom (99.95 percent of its mass) is orbited by tiny electrons (only 0.05 percent or less of the overall atomic mass). And as you've probably heard, an analogy is to think of the...

under what condition should the Bohr atom behave classically?

How come atom was proven to exist just because the electron was discovered in 1874, atom was like a fad of truth on early 1800s right, where atom was pictured at that time like a small brick of ball and nothing else (no electrons, neutrons, protons, parts, etc) and on that year also, chemistry...

Homework Statement Question a) Briefly describe the Rutherford model of the hydrogen atom and mention any inadequacies that it might have. b) Describe the Bohr model of the hydrogen atom, and indicate the significance of the quantum number 'n' in the Bohr model. Homework EquationsThe Attempt...

Am I right to say that an electron in the lowest level of an atom cannot fall into the nucleus because to do so requires it to give up energy in the process and it . does not possesses the energy at this atomic level.Electrons in higher levels can give up energy and fall to a lower level if...

I'm quite new to quantum mechanics. I have a question, I'm coding a small game with my friends and I do understand the orbitals and I've even written a function in java to simulate the probabilities of ONE of those diagrams, but I do not know my scale just yet, can anyone tell me the width of...

If you were to condense an atom or group of atoms, the gravitational force would be very large because the atom is 99.9999999999996% empty, so making it 100% full would be like crushing a pound of tin foil into the size of a pen dot. If the density is so much it would make a huuuuge...

Good day all! I have a question that has been in my head bouncing around for a while and I figured the best resource would be here as I can't find anymore related information (Or I am just looking in the incorrect spot). My apologies if this is in the wrong section I wasn't too sure where to...

I found an old paper online (1962) I think, stating that bremmstahlung occurs between different neutral atoms in collisions. Am I correct in assuming that this will result in frequencies outside of the usual line broadening mechanisms? Thanks