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Molecules of a solid [closed]

Question: Molecules of a solid : (a) are always in a state of motion (b) move only when heated (c) move because they are loosely bound (d) do not move at all My attempt: I ...
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2answers
59 views

Molecules and electrons energy types

What are the types of energy that an atom or a molecule could have? For example they have kinetic energy, could they also have other types?
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2answers
188 views

Is the potential energy of molecules related to its temperature? [duplicate]

Do ideal gases have a certain potential energy at a certain temperature?
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4answers
2k views

Water in vacuum (or space) and temperature in space

So, water in vacuum will boil first and then freeze. I don't know how the freeze happens. As pressure lowers to zero, what happened to freezing point? (I know heat taken by vapor, and the water cool ...
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3answers
417 views

Potential energy curve for intermolecular distance

I'm trying to understand this curve better, but I can't quite figure out what "negative potential energy" means. The graph should describe a molecule oscillating between $A$ and $B$, however where ...
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1answer
91 views

What is opposite of electric field?

A negatively charged molecule will generate a field, an electric field, and it will repel all negative ions. So what does positively charged molecule generates that causes other positive molecules ...
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2answers
388 views

How to determine what an object is composed of?

Heads up: This question has never been asked (here) before the way I will ask it here, so let's shed some light on it a bit. Prelude and anecdote(can be skipped): The other day I was walking home, ...
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1answer
39 views

Molecular formula of a compund [closed]

I have no idea on how to get information out of this one. A compound contains only hydrogen and nitrogen. Nitrogen makes up for 87.4% of the mass. A sample of this have a density of 0.977 g/L at ...
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1answer
345 views

Are valence electrons in nonpolar molecules localized/delocalized?

Are valence electrons in non-polar molecules localized or delocalized? I'm quite confused about the whole electron localization and delocalization business. I'd love a simplified explanation that a ...
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5answers
385 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 ...
2
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1answer
304 views

If the source of sound is vibration, why can't we “hear” a object whose molecules are vibrating?

According to our physics textbook, the source of sound is vibration. According to our chemistry textbook, substances in solid state have molecules vibrating in a fixed position. So why can't I hear my ...
4
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2answers
135 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 ...
3
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1answer
94 views

Relative weights in rotational bands of symmetric diatomic molecules

In an old paper, Ehrenfest 1931, the introduction starts off as follows: The band spectra of symmetric diatomic molecules show certain striking differences from those of asymmetric molecules. For ...
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1answer
84 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 ...
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3answers
856 views

Does gas spread out equally everywhere?

An excerpt from this page: Gases can fill a container of any size or shape. It doesn't even matter how big the container is. The molecules still spread out to fill the whole space equally. That is ...
3
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4answers
363 views

Molecule vs Crystal

Feynman mentions in his lectures: ...the concept of a molecule of a substance is only approximate and exists only for a certain class of substances. It is clear in the case of water that the ...
2
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1answer
234 views

Orbital of Hydrogen molecule

does anybody here know an analytical approximation of the bonding hydrogen orbital MOLECULE? I am looking for a good approximation to this orbital, that might be in some textbooks to get an ...
5
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1answer
2k views

Why does a breeze of wind make us feel cooler? [duplicate]

In my Astronomy class, I learned that temperature results from the speed of air molecules colliding into your skin. Thus, if the air molecules in the room have a high kinetic energy and thus collide ...
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2answers
1k views

Where does the Pauli Repulsive Force come from that counteracts the attraction between atoms and ions? [duplicate]

I'm learning about such things as ionic and covalent bonds, and the reason given for the ionic bonds is electrostatic attraction. However, if that were true, then the two ions would accelerate toward ...
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1answer
71 views

The Molecular Hamiltonian and the avoidance of Overcounting

Whenever I see the total non-relativistic molecular Hamiltonian, $\hat{H}_{molecular} = \hat{T}_{e} + \hat{T}_{n} + \hat{V}_{ee} + \hat{V}_{nn} + \hat{V}_{en}$ I always notice that the sums ...
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2answers
6k views

How to estimate the physical size of a molecule?

I'm reading some chemistry-related papers that employ concepts of droplet evaporation. Since I am no chemist, I am wondering: How can I estimate the actual size of a molecule, say succinic acid? An ...
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4answers
897 views

Can a single molecule have a temperature?

A show on the weather channel said that as a water molecule ascends in the atmosphere it cools. Does it make sense to talk about the temperature of a single molecule?
4
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1answer
105 views

For how long must a molecule remain stable to be considered “stable”?

In the Star Trek: Voyager episode The Omega Directive, Seven of Nine says that the Borg synthesized a molecule which was "kept [] stable for one trillionth of a nanosecond before it destabilized". ...
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1answer
359 views

Difference between Non-Polar and Dipole moment $\vec\mu$=0

Is there any difference between a molecule having $\vec\mu=0$ and being Non-Polar?
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0answers
191 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.)
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0answers
128 views

How large must the Quantum teleportation fidelity have to be in order for it to be useful?

This question relates and stems from my original question. Please read this one and the comments before answering this question. Quantum Teleportation Fidelity I know that for discrete variables ...
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2answers
772 views

What is the “direction” of the transition dipole moment? (Understanding Eq. 9.29, Charge and Energy Transfer 3rd Ed, May & Kuhn)

For a real vector $\mathbf{r}$, the direction is given by: $\hat{\mathbf{n}}=\mathbf{r}/\left|\mathbf{r}\right|$. The transition dipole moment is a complex vector. How do you define its direction? ...
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2answers
199 views

Why molecular forces do not obey inverse square law?

Most of the forces in physics obey inverse square law, but why molecular forces don't obey it.. Since molecular forces is also a form of electromagnetic force..
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1answer
105 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 ...
2
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2answers
840 views

Why is there a Global Minimum for the Morse Potential?

For Diatomic molecules, the Morse potential describes their potential energy as a function of separation distance between the two particles. My question is, what is the explanation of of the dip ...
4
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1answer
237 views

What's the underlying particle physics of endothermic reactions?

I don't just mean reactions that require heat to proceed, storing surplus energy in chemical bonds. I wonder about strongly endothermic reactions that suck heat out of environment. You take some ...
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1answer
3k views

Electric force in DNA molecule

Given that distance between O-H and N-H bonds are 0.11 nm and How do I compute the net force exerted from Thymine and Adenine? A hint given is: Hint: To keep calculations fairly simple, yet ...
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1answer
522 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
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1answer
256 views

Why do some liquid metals have anomalously-high surface tension/heat of vaporization ratios?

In a didactic article, Victor Weisskopf estimated the size of molecules in a liquid from measurements of their surface tension and heat of vaporization. If atoms are exceedingly small, then only a ...
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3answers
444 views

How do the molecules of reacting compounds proceed to form “Most Stable” molecule?

This question is a cross post from chemistry. I'm not very convinced with the answer there. So, I'm posting it here. I'm tutoring few students for Chemistry. During the course, I many times use the ...
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2answers
3k views

How to construct the Hamiltonian matrix?

I'm trying to understand if there's a more systematic approach to build the matrix associated with the Hamiltonian in a quantum system of finite dimension. For example, I know that for the ammonia ...
3
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1answer
88 views

What methods exist for us to measure the position and momentum of atoms that make up molecules?

In this paper, Localization of an atom by homodyne measurement. A. M. Herkommer et al. Quantum Semiclass. Opt. 8 no. 1, p. 189 (1996) (paywalled). the authors are able to localize atoms using ...
3
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1answer
68 views

Will a gas keep forever in a “perfect” flask?

I've been wondering about the porosity of materials, I know that, for example the air comes out of tires/balloons because (besides having huge gaps on the rim contact area/knot) they are made of a ...
2
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1answer
536 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- ...
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0answers
241 views

Electron hopping among molecules - Marcus equation

I'm running out of professors to talk to, and I need to clarify a couple of things for the sake of making a realistic model of electron travel through a mesh. This is about calculations of electron ...
2
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2answers
525 views

What's the difference between two Hydrogen atoms?

If we are given two Hydrogen atoms, would the only difference between them would be their quantum state (Energy level or eigen value, and the corresponding Orbital or eigen state) and their location ...
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1answer
438 views

Gas kinetic representation of trans-critical conditions

From a molecular point of view, can we think of the super-critical conditions as conditions where T and p are large enough that the collisions of gas molecules are frequent and powerful enough to ...
2
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1answer
608 views

Theoretical treatment of Hydrogen bond?

I would like to understand how the Hydrogen bond can be described through the Schroedinger equation. I don't need numerical methods that one uses them to simulate it, rather I need its treatment from ...
8
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1answer
210 views

Are Born-Oppenheimer energies analytic functions of nuclear positions?

I am looking for references to bibliography that explores the smoothness and analyticity of eigenvalues and eigenfunctions (and matrix elements in general) of a hamiltonian that depends on some ...
1
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1answer
66 views

Rotation of diatomic homonuclear molecule

I know that the rotation energy of a diatomic homonuclear molecule is $E_{Rot}=\frac{\hbar J(J+1)}{R^2 M}$. Does the axis of rotation depend on $J$? With respect to which axis does the molecule for ...
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4answers
452 views

What forces are at play when molecules wiggle (due to heat)?

What forces are at play when molecules wiggle (due to heat)? Or in other words, What makes them move?
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1answer
867 views

How the bond angle of a water molecule is measured?

How the angle of a water molecule is measured? The bond angle for water was first determined by vibrational and rotational analysis of its infrared absorption spectra. How is bond angle extracted?
2
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0answers
112 views

Is the translational information all that matters, or do we need to take into account internal states?

For anyone in this community that's familiar with quantum teleportation, I need desperate help. I am currently working on my senior thesis and my goal is to teleport a molecule. Background: So in ...
6
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1answer
2k views

What happens when you shake a can of soda?

Of course the CO2 comes out of the liquid, and it will even build up a lot of pressure if needed. The question is what happens at a molecular level to cause it to leave the liquid?
2
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2answers
344 views

Origin of Electromagnetic Interactions between Molecules

What is the origin of electromagnetic interaction between molecules? Anyway, it should have some relation with atoms. Also, These electromagnetic interactions are playing a major role in different ...