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Branch of Physics that Examines Atoms Relationships

Is there a specific branch of physics that can examine and calculate the strengths of atomic or molecular bonds and predict how they are going to break, putting into consideration the surrounding ...
1
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2answers
69 views

What is the energy of an atomic orbital?

When we refer to energy of an atomic orbital what is this energy ? is potential energy ? but if is potential energy then shouldn't be considered the whole potential energy of the atom ( potential ...
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1answer
56 views

What are some molecular systems which have quantum states that are measurably incompatible?

What I'm looking for is a molecular system, which we can produce in a lab, that is, A discrete variable system (ie, a finite dimensional hilbert space) It has observables that are incompatible with ...
1
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0answers
37 views

How to determine symmetry of the system from the term symbol?

I'm studying term symbols. I can derive them mechanically from the electron configuration using the complete table of microstates. Let's consider a typical example - an atomic carbon with the ...
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0answers
28 views

In what cases (precisely) are Hund's rules valid?

I can't find on any good source (such as a textbook) a precise specification about the cases when Hund's rules (especially Hund's third rule) for an electronic configuration of atom are valid (the ...
3
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0answers
35 views

Stability of saturated energy levels

In The Feynman Lectures on Physics, Vol. 3, Section 15-5, there's a discussion of the stability of various benzene ions. It turns out that the ions for which the all the energy levels up to a certain ...
5
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1answer
144 views

What are sigma and pi bonds in physics language?

Chemists often discuss sigma and pi bonds. To a physicist, it's not easy to figure out what these actually are, as discussions tend to be full of lots of chemistry jargon about "antibonding", "...
1
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0answers
176 views

Is there some connection between Band gaps and avoided crossings?

In abstract sense, are they one and the same phenomenon? We see band gaps when we consider Bloch Waves, etc... in periodic lattice and avoided crossings can happen even if we consider classically ...
1
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1answer
46 views

Exciton elements and exciton chemistry

An exciton is a bound state of an electron and a hole, much like a hydrogen atom is a bound state of a proton and an electron. Can a "helium" exciton be created, such that two electrons are bound to ...
2
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1answer
582 views

LCAO - Constructing a molecular wavefunction

I am a theoretical physics student and have been studying the LCAO (Linear Combination of Atomic Orbitals) technique from the perspective of a physicist. I would like to get some explicit ...
9
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2answers
188 views

What *really* happens to atoms in chemical reactions?

I am imagining that the occasional oxygen might be floating close enough to a certain calcium atom and take the two electrons, which will ionize them and they will now 'glue'. Maybe the same thing ...
1
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0answers
74 views

Scalar Multiples in Diagonalisation of Fock Matrix

I am currently trying to diagonalize the elements of a Fock matrix, $F'$ in an STO-nG basis. That is, I'm solving the Roothaan equations, $$F'C'=C'\epsilon,$$ by diagonalising $F'$ through taking its ...
3
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1answer
89 views

Trying to write a hartree fock program; confused about potential energy integral

The book I am working from has the following $$ {V}_{ij} = \int dr_1 Φ^*_i Σ_a\frac{Z_a}{r_1 - R_a} Φ_j $$ This is for the nuclear-electron attraction. Let's look at a simple case: a hydrogen atom....
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2answers
124 views

Can reactions be controlled electromagnetically

Since reactions involve the movement of electrons, Can't electromagnetism be used to control which path the electrons take and thus control the reaction?
2
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0answers
79 views

Are the $+\leftrightarrow+$ and $-\leftrightarrow-$ methanol rotational transitions dipole-allowed?

I am quite confused about the origin and justification of the rotational selection rules of methanol, and I would appreciate any help or references. As far as I understand, there are three irreducible ...
3
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1answer
160 views

What are physical reasons for chemical reactions? [closed]

I don't know what are the molecular reasons that two substance will form another substance. Why oxygen molecules can form to ozone molecules? Why hydrogen and oxygen makes water? What are the ...
4
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2answers
351 views

Does the Dirac equation ever get used in Physical Chemistry?

I'm just curious as to know if there are any examples in physical chemistry or condensed matter physics where the Dirac equation is preferable to the Shrodinger equation for making predictions on the ...
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1answer
710 views

Calculating with quantum numbers and shape of nodal shells

I'm attending in a chemistry course now, and in the beginning we scratch the surface of the quantum physics, which have led me to some problems. Mostly I understand all what we get until now, but ...
2
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1answer
140 views

Atoms attraction [closed]

Do atoms attract to atoms of same element? And would atoms attract to another atom for forming ionic or covalent bond? I basically want to know what would an atom be attracted to? (Except for ...
2
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2answers
69 views

Spin-$\frac{1}{2}$ particles in chemistry

Electrons and protons are spin-$\frac{1}{2}$ particles, so under a rotation by 360$^\circ$, their wavefunction changes by a sign. They are also commonly found alone in chemical reactions, especially ...
2
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2answers
1k views

Calculating the radius and potential energy of an atom?

Is there a general equation that gives the potential energy of any element at each energy level? I know that there is an equation for the potential energy of a hydrogen atom at each energy level but ...
2
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0answers
251 views

Why is the activation energy of combustion so large compared with regular bonding?

I wanted to know why combustion requires an activation energy and I found this article (see this too). It says that molecular oxygen ground state is a triplet state (according to Hund's rules), and ...
0
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2answers
2k views

Correlation energy - is it the difference between the Hartree-Fock energy and exact energy, or Hartree-Fock PE and exact PE?

For some reason I can't find anything stating it either way explicitly. What I'm talking about is this. Is this difference referring to potential energies or just energies in general? I assume it's ...
2
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2answers
236 views

Atomic orbitals

I just studied atomic orbitals in a theoretical QM class, and I'm left with several questions, that are probably more questions in quantum chemistry: Many orbitals seem to have a preferred axis - how ...
1
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1answer
135 views

Does O$^{2-}$ really exist?

In chemistry it is common sense that we have O$^{2-}$. But from a physical point of view, does O$^{2-}$ really exist as a negative ion? I mean, as an isolated ion. It is not apparent that a neutral ...
2
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4answers
705 views

Two soft questions about spin and the particle nature of electrons

How can we define spin as the spin of an electron around it's own axis if an electron is described by a probability cloud of finding an electron in a point in space? How does that probability cloud ...
2
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5answers
993 views

What laws (formulas) govern forces between atoms?

What laws (formulas) govern the fundamental forces of nature? For example, gravity is governed by the inverse-square law. I am thinking about how particles attract each other, but also repel. All ...
7
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1answer
2k views

Can we model Chemical Reactions using Quantum Mechanics? If so, what is the most complex reaction we can model?

Not a physicist or Chemist, just interested in QM and it's applications. I've been reading lately about Quantum Chemistry and it occurred to me that since we can model electron orbitals in QM and ...
2
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1answer
376 views

Chemistry from a physical perspective [duplicate]

I'm currently learning chemistry for the first time, and loving it. I have a reasonably good physics and maths background and it's great to see things like spherical harmonics in quantum mechanics "...
2
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1answer
104 views

Why does bringing N 1-orbital atoms together yield N levels?

A common example of this is that when bringing N hydrogen atoms together into a ring. Far apart, assume each electron exists in the 1s state. As we bring them together, instead of each electron ...
18
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3answers
8k views

What is the quantum mechanical explanation of the octet rule?

What is the quantum mechanical explanation of the octet rule? In other words, what makes the octet rule be true from a quantum mechanical view? How we explain what makes some atoms don't follow the ...
14
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3answers
672 views

Chemical reaction as state transition?

When considering diffusion of chemicals, the reaction part is business of chemical kinetics, where the relevant characteristics of different substances come from collision theory together with some ...
2
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2answers
176 views

Driving a solution of optical isomer molecules with the resonant frequency

What happens when we drive a solution of optical isomer molecules (enantiomers) with a microwave radiation in resonance with the tunneling frequency of the molecules (the frequency of the transition ...
3
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1answer
827 views

Why do hydrogen atoms attract?

That is, why is the potential energy with the orbitals overlapping less than with the Hydrogen atoms 'independent'. Similarly, why is a noble gas configuration stabler than if an electron were to be ...
14
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4answers
16k views

Why do covalent bonds form?

why in a covalent bond are "the bonded electrons are in a lower energy state than if the individual atoms held them at the same proximity"? Also is it correct that " I think when you start pushing ...
4
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1answer
11k views

Why is oxygen in a triplet state and what are the consequences?

From Wikipedia here and here: ''Almost all molecules encountered in daily life exist in a singlet state, but molecular oxygen is an exception.'' ''The unusual electron configuration prevents ...
2
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1answer
329 views

THT (Tetrahydrothiophene) absorption spectrum

I am looking for the absorption spectrum of THT. What is the best way to find these types of exotic material's spectral characteristics?
2
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1answer
231 views

Is it possible to mechanically isomerize an sp3 hybridized carbon center?

Imagine I have an sp3 hybridized carbon attached to four separate polyethylene chains. By pulling on the polyethylene chains in some manner, is it possible for me to mechanically isomerize the chiral ...
5
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1answer
295 views

Physical Chemistry: What's the relationship between orbital overlap and barrier shape?

This is a question for the physical chemists out there. For a given chemical reaction there is a barrier to traverse in order to proceed from reactants to products. Reactants e.g. an organic base ...