Questions tagged [quantum-chemistry]

Quantum chemistry is a subfield of quantum mechanics. Like its parent field, quantum chemistry focuses on understanding physical phenomena occuring at the atomic scale. Quantum chemistry however is more focused on providing useful descriptions of electronic structure to aid in understanding chemical problems (e.g. reactions, spectra, dynamics, ...).

Filter by
Sorted by
Tagged with
-1
votes
1answer
89 views

From a Quantum Chemistry Point of View how can I break Bonds without Heating?

Is it possible to dissolve/break bonds using strong alternating magnetic fields at high frequency? (Perhaps from tesla coils?) Could you use resonance to cause the bond to weaken over time? If so how ...
-1
votes
1answer
39 views

Help understanding the equation for Spin Energy in Zero Field

I’m working with a system that experiences spin frustration and for me this is the first time dealing with such a phenomenon. To grasp the concept, I’ve decided to go to the basics and read the ...
-1
votes
2answers
60 views

Why is the first affinity energy negative?

So, I've found a number of somewhat obscure responses to this question but I'm looking for something concrete: Why is the first affinity energy negative for most elements? I appreciate that this is ...
-1
votes
1answer
128 views

if the shared electrons in covalent bond revolves around their nucleus, how they hold the two molecules together? [duplicate]

Covalent bonds are formed by sharing electrons. The pictures depicting this bond make it seem like that the shared electrons stay in a fixed/limited place. What happens in reality? If they rotate ...
-1
votes
1answer
521 views

what is meant by stability and potential energy of molecules in cases of formation of bonds?

molecules form chemical bonds in order to gain stability. it is said that forming bonds leads to lower potential energy of molecules and makes them stable. what does stability mean? how formation of ...
-2
votes
2answers
506 views

What is the magnetic quantum number -1 vs +1?

In my book it states the magnetic quantum number “$m_\ell$" is the spatial orientation of the orbital with respect to a standard set of coordinates. I get what $n$ and $\ell$ is, but what does it mean ...
-2
votes
1answer
42 views

What is the physical significance of the fact that spin operators do not commute? [closed]

So we looked at the Stern-Gerlach experiment and I understand the basic principle; when a stream of silver atoms is passed through an inhomogeneous magnetic field, and the Ag atoms are deflected ...
-2
votes
1answer
159 views

Creating Pi Molecular Orbitals from P Atomic Orbitals

As shown in the image, we have two free p orbitals in ethene but we need two p orbitals each for the bonding and anti-bonding orbital. That is a total of four. What is the concept behind this?
-2
votes
3answers
57 views

Particle-wave duality for atoms [closed]

Hmm Hello . I was wondering if we could apply the particle-wave duality of a subatomic particle for an entire atom.I know that atom is better described as space but could we apply the de Broglie ...
-2
votes
1answer
272 views

why molecules gain energy when heated?

molecules in solid or liquid or gas gain kinetic energy when heated. why is it like this? I request explanation in details please
-2
votes
1answer
323 views

Radial expectation value for particle in a cubic box [closed]

A hydrogen atom is in a cubic box with side lengths equal to $\require{mediawiki-texvc}\pu{100 \AA{}}$. For what value of $n$ (principal quantum number) will the expectation value of the radius be ...
-2
votes
1answer
77 views

Do all single-electron species have the same orbital energies? [closed]

This picture from Ebbing's General Chemistry [1, p. 234] shows the electron orbital energies for a hydrogen atom, where each subshell belonging to the same principal quantum number ($n = 1, 2, \cdots$)...
-2
votes
1answer
43 views

Structure of atom [closed]

Consider one He+ ion in exited state(n=5).In the answer it is given that no. of spectral lines produced is 4 not 10.can't we use the general equation?
-2
votes
1answer
88 views

Uncertainty Theorem [duplicate]

What is the physical meaning of Heisenberg's Uncertainty Principle? We have derived it mathematically but what is the logical explanation for it?
-2
votes
1answer
718 views

Why the intensity vs. frequency graph initially increases for black-body radiation?

Max Planck had said that $E = n h \nu$ in his quantum theory. Then according to it, as the frequency of the light emitted increases, so the light's intensity should decrease. But it is not in the ...
-2
votes
1answer
107 views

Chemical Anti-bonding and Pauli repulsion [closed]

We can explain chemical anti-bonding just using the Pauli repulsion correct?Let's take He2. 2 atoms of He share 4 1s electrons and since the magnetic spin for electrons has 2 values there would be 2 ...
-2
votes
1answer
156 views

Electron Energy Levels? [closed]

New to chemistry; In my book it talks about electrons in atoms moving from one energy level or shell to another and denotes this by n. How does this exactly happen, do electrons move to different ...
-2
votes
1answer
69 views

How can an atom have 2 outer shells?

For example, my textbooks says how many electrons in the outer shell in Nickel? and it says the answer is the electrons in both the d shell and s shell. Doesn't shell equal= n quantum number? And n=4 ...
-3
votes
1answer
75 views

Are the electrons in an atom always 'locked' with their proton?

Suppose you have a single atom, say carbon, carbon has six electrons and six protons. Now is there anything associating the six protons locking the six electrons other than coulombic forces? When we ...
-3
votes
1answer
88 views

A question on spin of an electron [closed]

Can an electron have zero spin? In para hydrogen, since the nuclei have opposite spins, the they add up to 0. So is it true that one electron can have zero spin?
-3
votes
1answer
581 views

Identical particles: Why is triplet oxygen more stable than singlet oxygen?

Quoting from Eisberg Resnick Quantum Physics: If we consider space variables of two electrons (identical particles) to have almost the same values, then their wavefunctions are 'almost' identical ...
-4
votes
1answer
102 views

Why in Hamiltonian for hydrogen atom we have $\nabla_e$ and $\nabla_N$ and one does not operates on other? [closed]

Laplacian is $$\frac{\partial ^2}{\partial x^2}+\frac{\partial ^2}{\partial y^2}+\frac{\partial ^2}{\partial z^2} $$ Then why in Hamiltonian for hydrogen atom we have $\nabla_e^2$ and $\nabla_N^2$ and ...
-4
votes
1answer
47 views

Which of the following would be an example of something that is quantized? [closed]

How do we defind quantized there, why it is climbing a flight of stairs? Thank you!
-4
votes
0answers
26 views

Electronic Configuration of Lanthanum [duplicate]

Lanthanum has electronic configuration [Xe] 4f0 5d1 6s2. Why is the 4f sub-shell not filled even though we know that 4f is filled before 5d subshell? I know that for some elements energy level of 4f&...
-5
votes
1answer
41 views

What is the purpose of the equation [closed]

In my chemistry class we solved the equation wavelength = h/mv for finding the mass of a baseball and were given all of the other variables. I know that this equation has to do with wavelength of ...
-6
votes
1answer
90 views

Reaction of HF in water [closed]

I was wondering, if we put $\ce{HF}$ into a glass of water the acid will be dissolved according to this reaction: $$\ce{HF->F- + H+}$$ Now there is a proton travelling across the water. All $\ce{...
-7
votes
1answer
42 views

Wave-particle duality [closed]

Can I get an answer stating some analogies on how electrons behave like a wave, and what does it even mean for an electron to behave like a wave? Also, if going around the nucleus, is electron a real ...

1
20 21 22 23
24