Molecule Definition and 462 Threads

Hi, I'm an undergraduate taking the basic quantum classes and on my own, I'm trying to wrap my mind around how symmetry and group theory applies in Q.M. and theoretical physics in general; it's coming along slowly but surely! Can someone please explain why the ammonia molecule is said to...

What would happen if we placed a hydrogen molecule in a box with sides less than the Bohr diameter. That is, a box so small the electrons could not orbit around the protons at a distance of a Bohr radius. What state would the two electrons and two protons take?

Can someone post the most precise atom or molecule real pictures at present?

Homework Statement A diatomic molecule, when excited, can vibrate in such a way that the relative distance between the two atoms, r(t), executes periodic oscillations. If the potential energy of the molecule as a function of r is given by V (r), the time dependence of r(t) is identical to...

Homework Statement Molecules in an ideal gas collide with each other at random times. The probability distribution governing the time between collisions is P(t) = Ae^(-bt). (a) Find the value of A so that P(t) is correctly normalized. (b) Find the average time between collisions, t. This...

The ionization of potassium is 4.34 eV; the electron affinity of iodine is 3.06 eV. At what separation distance will the KI molecule gain enough Coulomb energy to overcome the energy needed to form the K^+ and I^- ions? I'm looking at the solution to this problem and I'm not understanding how...

Do you have any idea what molecule this is? They say it is attributed to patience. Thank you! :)

Homework Statement Hi everyone! first post here :) Basically, the question is as follows: Consider a hydrogen fluoride molecule (atomic mass of H is 1g/mole and of F is 19 g/mole). 1. Write the energy of the system in terms of the displacements of both atoms. There are other questions...

Hey, I am trying to figure out some research for a department at school, and need some chemistry info. Basically, I am comparing D2O (Heavy water) HDO (Semiheavy water) and H2O (Light water) NOW... each of them have different pH levels. What does that mean that they each have...

I can't seem to find an answer to this. The question is: If I obtained Deuterium oxide from let's say a plant that manufactured it in some part of the world, and then obtained Deuterium from another plant manufactured from some other place in the world, is it possible for them to have...

Hi , If I used electrons to ionize Oxygen gas by accelerating the electrons and then collide with Oxygen molecules , What is the electron velocity needed to do this ionization ?

Homework Statement An ammonia molecule (NH3) has a permanent electric dipole moment 5.0 x 10^-30cm. A proton is 2.50nm from the molecule in the plane that bisects the dipole. What is the electric force of the molecule on the proton? Homework Equations F = QE = eE_yj =...

Hey, I cannot solve this problem. Please help me. In the H2 molecule, the Pauli exclusion principle demands that the wavefunction of two protons be antisymmetric under the interchange of the two proton coordiates. Based on this, explain the (a) In the spin-triplet states of two protons...

Can you help me identify simplest naturally occurring self-replicating molecule? Or even better, let's make one artificially... where "self-replicating molecule" is such that contains at least two different atoms, it reacts with other atoms and molecules so that it accumulates duplicates of...

Homework Statement The potential energy of two atoms in a molecule can sometimes be approximated by the Morse function, where r is the distance between the two atoms and A, R, And positive constants with S<<R. Sketch this function for 0<r<∞... ##U(r) = A ( (e^{(R-r)/(S)}-1)^2 - 1) ## This is...

Homework Statement Within cells, small organelles containing newly synthesized proteins are transported along microtubules by tiny molecular motors called kinesins. What force does a kinesin molecule need to deliver in order to accelerate an organelle having mass 0.028 pg from rest to 2.8...

Hello all, Many Physics texts simply say that atoms "vibrate" when heat energy is transfer to a metal bar when it is heated. Or that molecules vibrate as the result of heat transfer. I'm trying to understand what makes an atom or molecule "move" or oscillate when energy is given to it. If I...

http://img43.imageshack.us/img43/2916/95953925.jpg I understand molecule #1 is sec-pentylcyclohexane But how would you call molecule 2? Please give common and IUPAC names (no need for too much detailed explanations) Thank you.

Eigen - problem for atom ##1## (\frac{p^2_1}{2m}-\frac{e^2}{2\pi\epsilon_0r_{1a}})|\varphi_a^{(1)} \rangle=E_a|\varphi_a^{(1)}\rangle for atom ##2## (\frac{p^2_2}{2m}-\frac{e^2}{2\pi\epsilon_0r_{2b}})|\varphi_b^{(2)} \rangle=E_b|\varphi_b^{(2)}\rangle When I write |q...

Homework Statement What happens to a water molecule if it is hit by a high energy electron or photon?Homework Equations The Attempt at a Solution My knowledge of chemistry is very limited, and my guess is that it would be ionized: e + H_2 O \rightarrow H^+ + OH + 2e Here, a high energy...

√Homework Statement Carbon monoxide molecule, which has a reduced mass of 6.85 amu, absorbs infrared radiation wavelength of 4.6um. if the absorption is due to vibrational transitions, calculate the strength of the bond in molecule Homework Equations u=(m1*m2)/(m1+m2) The Attempt at...

How to calculate the energy of the bonding state and antibonding state of a hydrogen molecule? and also how to plot the bonding and antibonding wavefunctions. I have solved Ψ(r,θ,Φ) for a hydrogen atom. and calculated the energy states of it with complete analytical approach. now, i need to...

I am doing my research on quantum transport. Now, I have some confusions- my questions and my idea about those go like this- 1. what is the ground energy state of hydrogen molecule? >> as long as i know, hydrogen molecule has a bonding state and an antibonding state. i think bonding state has...

Heres the question: http://img266.imageshack.us/img266/5071/sar2.png I have no idea how to answer either of these questions. I know that the methyl group attached to the carboxyl groups alpha carbon will decrease the acidity due to electron donating properties. It doesn't look like the...

Dear all, In classical molecular dynamics simulation initial velocities are generated using the so called Maxwell distribution. At low temperature it's no longer effective, so I'm wandering whether there is a similar way to generate velocities at low temperature taking into account quantum...

Hi My current understanding is of a water molecule able to absorb radiation by a transition, a change in the vibration or rotation. But if we consider that the molecule has three axes of rotation, surely one of these axis can be parallel to the molecular dipole, so shouldn't it be impossible...

Homework Statement Two identical carts (of mass m) are free to move on a frictionless, straight horizontal track. The masses are connected by a spring of constant k and un-stretched length l_{0}. Initially the masses are a distance l_{0} apart with the mass on the left having a speed v_{0} to...

H20 is polar in nature. It is fundamentally because oxygen is more electronegative than hydrogen and the shared electrons tend to be near oxygen. This may be because the atomic number of oxygen is more than that of hydrogen. But in the bond I don't understand how the 2 shared electrons...

I have heard that iron is quite special in that no matter how much temp. and pressure is present, it will not change to a molecule of greater atomic number. I keep wondering about the geometry of the arrangement of protons and neutrons in the iron atoms' nucleus that could account for this...

Derive an expression for the number of impact of gas molecules on unit area in unit time in terms of the number of molecules per unit volume, n, and their mean speed, <c>. Explain the assumptions you make. A disc of radius "a" rotates with constant angular velocity "omega" in a gas at low...

Question: The amount of heat required to convert 1g of ice into vapour is approx. 3000J. Estimate the energy required to separate one molecule from a single neighbour, assuming that in ice, each H2O molecule has four nearest neighbours. [Mr(water) = 18) My reasoning: 3000 x 2 / [1/18...

Homework Statement I have to find the hamiltonian for a diatomic molecule, where the molecule can only rotate and translate and we supose that potencial energy doesn't change.Homework Equations The Attempt at a Solution Okey so I used Spherical coordinate system such as the kinetic energy of...

Since the HCl molecule has a non vanishing dipole moment, it is allowed to have pure rotational spectrum. If I understand this correctly then it's possible to excite the molecule in such a way that its vibrational energy stays the same while its rotational energy increases by some amount. This...

If I understand the equipartition theorem more or less well, if I heat up a gas then the energy I have spent to heat it up should be equally distributed to the rotational part and vibrational part of the molecule dynamics. Let's take the molecule of CO, I think it has 5 degrees of freedom. 3...

I was just wondering that when we have a molecule, and you introduce heat, the molecule starts to get translation, rotation and vibration energy. I'm considering just a molecule with two atoms and one axis which binds them together. Now the real question is that why is there only two axis in...

"Given that the maximum molar absorption coefficient of a molecule containing a carbonyl group is 30 dm3 mol-1 cm-1 near 280 nm, calculate the thickness of a sample that will result in (a) half the initial intensity of radiation, (b) one-tenth the initial intensity." My attempt: What is...

Homework Statement A atom had a threefold degenerate ground level, a non degenerate electronically excited level at 3500 cm^-1(setting the energy orgin as the ground electronic state energy of the atom ) and a threefold degenerate level at 4700 cm^-1 . Calculate the electronic partition...

I'm trying to follow Feynman's explanation on page 9-3 of Volume 3 of The Feynman Lectures on Physics. I've attached a copy of the section in question. To normalize CII he notes that < II | II > = < II | 1 >< 1 | II > + < II | 2 >< 2 | II > = 1 I am not clear how he derives the conclusion...

Hey all, I'm new here, but used to frequent in high school when I was having a lot of trouble with Physics. Now I'm taking O Chem and figured this could be a great resource to use again. I had this question on a quiz today, just wondering if I did the Claisen rearrangement for this particular...

Homework Statement Estimate the precise value for the specific heat of a nitrogen molecule at T=13.6K Homework Equations I'm pretty sure the correct equation is: Cp = (7/2)*R + R((hv)/(kT))2 *((e(hv/kT))/(e(hv/kT)-1)2 So R=8.314 J K-1mol-1 T=13.6K h=6.626*10-34m2kg s-1...

Has anyone made a calculation for example, how much (or the mean) time it takes for an individual gas molecule to be displaced a distance of one meter (measured straight) from its original location? For example, air molecule at ambient pressure with a mean free path of 68 nm. That would be...

Just saw a molecule on TV. It was a tattoo. Want to identify it. C8H8N4O2 Is there a way of researching it? Or I guess I can just give up and ask...

Is the VSEPR model a tool to help us visualize what is happening to molecules, or do the atoms really take on the shape of something like a trigonal bipyramidal?

Hi, Does anyone know where I can find post-hartree-fock calculation benchmarks for dissociation energy of the NO molecule. Or even just the equilibrium energy of the NO molecule? I am looking for cc-pVTZ basis set results but I can only seem to find augmented basis set results. Thanks.

Homework Statement http://postimage.org/image/cky823nof/ Homework EquationsE=kq/r^2 The Attempt at a Solution I figured I would just find the electric field produced at point * by each individual charge and then add them. For example if I were to set E1 to be the top molecule the field...

http://www.bbc.co.uk/news/science-environment-15637867" Cool or what.

Homework Statement Hi everyone! I'm trying to solve a problem involving 3 equal masses (m) arranged in a 45-45-90 right triangle, each mass connected to the other two by a spring, and all the springs have the same spring constant (k). So it should look like this: Where I have made a...

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 An amonia NH3 molecule in the figure has three hydrogen atoms, which form a equilateral triangle as the base of a pyramid. At the top of the pyramid is the nitrogen atom. The length between any two hydrogen atoms is 9.4x10^-11, the length from nitrogen to any of the...

Homework Statement Have a H2 molecule in a constant E field. This produces a shift in the on site energies of the 2 H atoms so they have energies ε-δ,ε+δ. δ is proportional to field strength. 1)Calculate the tight binding density matrix when the hopping integral is -1. (γ=-1) δ is positive...