1
vote
0answers
68 views

Why is graphene the only (stable) 2D sheet structure? [duplicate]

I know that Carbon molecules can form different structures depending on how they bond with each other: graphite, diamond, graphene and fullerene. As far as I understand, graphene is just a "sheet" of ...
1
vote
1answer
71 views

Wigner Threshold law in Photodetachment and Photoionization

I am writing this question here because I have a problem in understanding the Wigner Threshold law in Photodetachment and Photoionization. The Wigner Threshold Law is given by: $\sigma$=$E^{L+1/2}$. ...
3
votes
1answer
61 views

Measuring Atomic Radius of a Noble Gas

How exactly can you measure the atomic radius of a noble gas such as Neon or Helium accurately? Would liquefaction help? I also heard that the aforementioned gases are the only common elements which ...
7
votes
3answers
449 views

Hot water freezing faster than cold water

This question has puzzled me for a long time. There is already a question like this on Physics.SE. John's answer to the question seems quite satisfying. But when I googled the cause I found this and ...
0
votes
0answers
15 views

Why photoelectron imaging is a 'complete' measurement?

In many articles and books, it says that photoelectron imaging gives a 'complete' information. What is mean by 'complete' measurement or a 'complete' information? Through photoelectron imaging ...
3
votes
0answers
79 views

What is a covalent bond?

What is a covalent bond, quantum mechanically? How does it hold the two atoms together, and at one point can you qualify the electron as being shated between two atoms, versus feeling attractive ...
1
vote
0answers
29 views

Covalent Bonds, Varities and Limits!

Related:http://chemistry.stackexchange.com/q/9459/ I was wondering, covalent bonds tend to share two electrons, apparently rarely more than three, and normally between two electrons. Can someone give ...
0
votes
0answers
14 views

Dipole and multipole bound state anions: Do these bound electrons behave exactly like conventional electrons in the molecular orbitals?

Recently, I read about dipole and multipole bound anions. Dipole bound anions are those, if I understood correctly, when an electron is attached electrostatically on a neutral molecule which is polar. ...
3
votes
1answer
73 views

Using the fine structure constant to measure atomic and molecular sizes

This is kind of a coursework question but it bring up some really interesting things about the fine structure constant $\alpha$ so I wanted to post it to not only make sure I understood something but ...
1
vote
1answer
130 views

Why is the orbital angular momentum of a pi electron along the axis of two atoms' molecule one?

I'm reading quantum chemistry. The book says that the orbital angular momentum of a $\pi$ electron along the symmetry axis of a molecule made up of two atoms is $\pm 1$. I think this is a primary ...
0
votes
0answers
36 views

Difficult to visualize Franck-Condon overlap

The franc condon principle says about the vertical transitions, means the coordinates of the nuclei remains unchanged during an electronic transition. But, what is the physical meaning or how to ...
1
vote
5answers
343 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 ...
4
votes
2answers
109 views

Why is it energetically favourable for molecular bonds to form from a QM point of view?

For example, if you have two hydrogen atoms and an oxygen atom, they are all electrically neutral and don't attract each other. But then if they manage to get "close enough" somehow they snap together ...
1
vote
1answer
69 views

Difference between photo electron spectrum and photoelectron angular distribution

I am trying to learn the Photoelectron velocity map imaging. While I was going through the article "Chem. Soc. Rev., 2009,38,2169-2177", it is said that the "photoelectron spectrum reflects the energy ...
0
votes
0answers
158 views

Breaking of a covalent bond

When a bond between two atoms is broken, why only one electron is released. Why not two? (as two electrons make up a covalent bond.)
1
vote
1answer
90 views

Thermionic emission, delayed emission and predissociation

In molecular photodissociation, the thermionic emission, delayed emission and predissociation are the same? Otherwise, what is the difference between them? My question is not about the solids, but I ...
1
vote
1answer
446 views

Why it is called a Newton Sphere? (Velocity map imaging)

In velocity map imaging (photo-dissociation and photo-emission), the ejected particles form a newton sphere. I didn't really get the concept why it is called a "newton sphere" and also why at the ...
2
votes
1answer
423 views

Explanation on Atomic Orbitals and Molecular Orbitals

We were reading about atomic structures and bond making and my teacher told me that when two atoms are fused or when they make bond, two orbitals are formed. 1-Bonding Molecular Orbital & 2- ...
9
votes
4answers
2k views

Does it exist a free good molecule / atom simulation software?

I'm looking for a software or software package (for example C/C++) that can simulate a lot (say thousands at least) of molecules in action (ie. in movement or attached to say static walls). I have ...