Atoms Definition and 880 Threads

I am a freshman in DFT calculation. I don't understand the DFT method clearly,but I want to use DFT to do some calculations. My question is that how how can I get the potential energy of each atom in a structure using DFT package ,which I have done by using classical MD method in Lammps(the...

If we prepare a chain of flourine atoms: F-F-F-F-F-F-F-F-F-F-F-F-F-F-F-F-F-F-F we can construct the band structure shown. I'm using flourine as an example but my question can be generalized: What do we know about the conductivity of a material (such as this 1D chain) when the fermi level lies in...

μ/T represents the change in entropy if we change the number of particles,, so according to the fundamental assumption of statistical mechanics μ/T should tell us about the tendency of two systems to exchange particles... but I am having a hard time imagining how rotational or vibrational...

Hi, I am trying to make a Magnesium source by curling up a tungsten wire with a block of Mg inside. Then by setting electricity to the tungsten wire, the Mg is heated and you get what out? Magnesium atoms? Magnesium ions? Thanks a lot /Carnot

In this vid, Faynmen explains what a fire really is: just watch from start till 1:22 He says that sometimes carbon repels air(O2) and sometimes they attract each other. If they attract, they start a fire. Whether they do repel or not is dependent by the distance between them or their...

I don't get why for hydrogenic atoms the 2s and 2p orbitals have the same energy. i do get it mathematically, but I am thinking that the fact that there are angular nodes in 2p and not in 2s MUST affect the energy!

Homework Statement A neutron moving with speed v makes head on collision with a hydrogen atom in ground state kept at rest. Find the minimum Kinetic energy of the neutron for which inelastic(completely of partially) collision may take. (mass of neutron=mass of hydrogen=~1.67*10-27)...

1. Homework Statement This was a question on an exam I took a week ago in inorganic chemistry. The problem statement was like: "We have two molecules, H2CCH2 (ethene) and F2CCF2 (1,1,2,2-tetrafluoroethene). Which bond angle is greater? H-C-H in ethene or F-C-F in 1,1,2,2-tetrafluoroethene?"...

Homework Statement i) The average concentration of 222Rn in air inside a building is 20Bqm-3; what is the average concentration of Rn in atoms per cubic meter? ii) In a sealed room of volume 50m3 what activity of 238U in a piece of porous rock would eventually give rise to this 222Rn...

Homework Statement In a classical gas of hard spheres (of diameter D), the spatial distribution of the particles is no longer uncorrelated. Roughly speaking, the presence of n particles in the system leaves only a volume (V − nv_0 ) available for the (n + 1)th particle; clearly, v_0 would be...

Homework Statement A crystal contains N atoms which posses spin 1 and magnetic moment \mu. Placed in a uniform magnetic field B the atoms can orient themselves in three directions: parallel, perpendicular, and antiparallel to the field. If the crystal is in thermal equilibrium at temperature...

The elements above iron are formed in a supernova. If that is the case, I don't see why we should find lumps of gold, lumps of uranium, lumps of cobalt, lumps of nickel. Why isn't it the case that all elements are just swarming around randomly with normal distribution. I put this under...

number of atoms in FCC gold cube with only the radius given! 1)it is given that the radius of a gold atom sphere is 144.2 pm, gold is packed in an FCC manner Give the ratio Ns/Nv as a function of L (gold cube side) and a parameter of FCC latice, knowing that Ns is the number of surface...

atoms would be impossible in a universe ruled by an inverse-cube law because there would be no stable orbits for electrons. The above sentence comes from Rees' book Just Six Numbers. I don't get it. Why would an inverse-cube law affect the stability of electron orbits?

Hello i need help in this question it is given that the radius of a gold atom sphere is 144.2 pm, gold is packed in an FCC manner Give the ratio Ns/Nv as a function of L (gold cube side) and a parameter of FCC latice, knowing that Ns is the number of surface atoms and Nv is the...

Atoms, and therefore matter, is made of protons and neutrons, which are in turn made up of quarks, up and down flavors, is it not possible that other matter may be made up of different quarks, so as to make different atoms, that would be very different to those we already know of and also...

In Lorentz Ether Theory, object really get contracted, for example, a 6 foot man would become mere 1mm when traveling near the speed of light. They say SR and LET can't be distinguished because the performance of contracted atoms, molecules, etc. would be the same. Meaning if you were mere 1mm...

Homework Statement Consider a paramagnetic material. The magnetic field generated by each dipole in the material is 1/30 T. What is the magnetic field at a given spin, due to the presence of nearby spins? Homework Equations The Attempt at a Solution So I need to multiply 1/30 by...

We've solved for several systems, the hydrogen atom for instance, and one of the properties of these is that it doesn't matter what excitation state you look at, they are stationary states, the Hamiltonian is constant in time, so where's the impetus on an excited atom to radiate light if it's in...

hi all. i am trying to calculate the interaction between two excited hydrogen atoms, using degenerate perturbation theory. but comes up a few problems, any helps will be greatly appreciated. the perturbation has the form: H`=e3/R3(XaXb+YaYb-2ZaZb) where the R is the distancee between two...

Perrin got his nobel prize because of his experiment on brownian motion, which is thought to have proven the existence of atoms i cannot understand that if you see an array of dots from STM, i believe you demonstrate the existence of atoms but i cannot see why perrin's experiment or...

Homework Statement I don't really understand the problem wording. What do they ask me exactly? Here it goes: Consider the potential energy V(r) of an electron in an atom whose atomic number is Z. Calculate the potential energy aproximating the distribution of charge of the others Z-1...

Hello guys :), if we magnetise Cs atoms with a magnetic field (or basically any other method like pumping), and got all the spins (moments) aligned in 1 direction, and then turn the cause of the alignment off, how will the decay profile look like? is it going to be a clean exponential decay...

Hello, I am looking what maximal velocity was reached for some atoms which have at least 1 electron. It can be ionized atoms, but still must have at least one electron. Thank you.

Homework Statement I'm having trouble with this. I need to calculate the number of atoms in iron. How do I do this? For example if I had 1 KG of iron, how many atoms are in it? Homework Equations I need to give an answer in scientific notation A x 10^B A being 1 significant...

Homework Statement The potential energy of two atoms in a diatomic molecule is approximated by U(r)=a/r^12 - b/r^6, where r is the spacing between the atoms and a and b are positive constants. Find the force F(r) on one atom as a function of r. Make two graphs one of U(r)...

Homework Statement Silicon at T= 300K contains acceptor atoms at a concentration of Na = 5*10^15 cm-3. Donor atoms are added forming an n-type compensated semiconductor such that the fermi level is 0.215 eV below the conduction band edge. What concentration of donor atoms are added...

Hi, I've been thinking about atoms a lot lately, and I've tried to search on internet but did not find any comforting answers yet. So (yes I'm an amateur) there is like 100+ known elements that's possible to combine together to form another compound. My question here is: Would it be...

Homework Statement The total number of atoms in 1.00 g of CaCO3 (MM = 100.0 g/mol) is: The Attempt at a Solution My solution: 1.00 / 100.0 = 0.01, then 0.01 x 6.022x10^23 = 6.022x10^21 atoms. However, the correct answer is 3.01 x 10^22. How was my approach wrong and did I miss any...

At what distance do 2 hydrogen atoms (not ions) begin to attract each other? No, this is not a homework question. I am 58.

Homework Statement The figure shows a potential energy curve for the interaction of two neutral atoms. The two-atom system is in a vibrational state indicated by the heavy solid horizontal line. (a) At r = r1, what are the approximate values of the kinetic energy K, the potential energy U...

Hi I want to figure out how to calculate the temperature at which more energy is required to keep hydrogen and oxygen together (as in the case of H2O) than to separate them...in other words the temperature at which hydrogen and oxygen will no longer combine due to extreme temperatures. How...

I don't understand atoms that well and the thought is so surreal. Can someone please try to help me understand?

I AM TRYING TO PROGRESS IN THIS PROJECT AND ONLY SEE ONE DIRECTION PLEASE IF YOU HAVE ANY KNOWLEDGE OR THEORY OF THIS PLEASE INCLUDE IT! Edit: personal information deleted I’m a sophomore at High school in Arizona. Although I’m most likely not as smart as most people on this forum, I’m...

We know everything on Earth is made up of atoms and molecules, and most likely everything in the solar system, but how do we know everything in the universe uses them, and not something else? The Big Bang would cause things to have similarities, but different parts of the universe could still be...

How many atoms are in one mole of the element Lead(Pb) -Intrepid Elder

It is common to see this line: "atoms are mostly empty space". That line appears inadequate and misleading. Atoms are ultimately made up of electrons and quarks. Electrons and quarks are by definition 'point particles', meaning they have no spatial extent. So there is nothing there that takes...

What the title says

What are the criteria for an atom to have non-zero nuclear spin? This is not homework. Thanks, Jake

Hello, why much substances have one atom when aren't gas and 2 same atom united when are gas (for example N and N2, O and O2) ? Thanks!

Is the reason behind the vibrating the movement of electrons from a stable to a excited state? My quest for knowledge began with this question..."How exactly does light transform into heat--for instance, when sunlight warms up a brick wall? I understand that electrons in the atoms in the wall...

Problem: The adjacent lines in the pure rotational spectrum of 35CI19F are separated by a frequency of 1.12 x 1010 Hz. What is the equilibrium separation of the atoms in this molecule? The attempt at a solution So, the equation I think I need to use to find the equilibrium separation...

This may be a simple question, but I still haven't a clear answer to it. How do atoms bond together? What force is used to bond them together?? (Please if you could answer both of these questions it would be great.) Thanks.

I'm a bit confused about quantum entanglement. First of all, how exactly do you entangle two atoms? I've heard about how they entangled atoms in quantum teleportation experiments, but I don't get how they did it. I've heard that the atoms must "interact", but what exactly does that mean? Do they...

To what extent does the Schrodinger equation apply to an atom as a whole?

This question is pretty straightforward, but I just can't seem to find the answer.. What is the reason that electrons only exist in shells and never between them? A hint that was given to me was to "think about quantum energy". I was thinking because if they wouldn't exist in shells, then...

Homework Statement When specially prepared Hydrogen atoms with their electrons in the 6d state are placed into a strong uniform magnetic field, the degenerate energy levels split into several levels. This is the so called normal Zeeman effect. A) Ignoring the electron spin what is the...

When we provide thermally or optically en energy higher than the semiconductor bandgap we create elctron-hole pairs, that is electrons are extracted to the valance band and they become free to move inside the crystal. My question is: are the semiconductor atoms then ionized, which means for...

Are there ever atoms being added to the universe? If not could we in the future be able to follow an atom through several different changes that it might experience?

I am trying to get the most complete picture of the structure of atom. I understand generally how elements and molecules are formed, however the last thing I was taught about atoms was 10 years ago. I was told about the electron proton and nuetron and that's it. I know this is just the basic...