Recent content by ani4physics

Hi all. I have been thinking about a very simple question, and I am a little confused. We know from time-independent perturbation theory that if the system is perturbed by the external perturbation λV which is much smaller compared to the unperturbed hamiltonian H0, we can write the ground state...

so what I did is right?

Yeah it is. Could someone please tell me if I did it right. If yes, then I will post the next part of the problem. Thanks guys.

1. Consider Bohr Hydrogen atom with counter-clockwise electron orbit in the xy plane with intial position r(0)=-a0y. The angular frequency of the orbit is w. Derive an expression for the position of electron at a later time t, r(t) in terms of a0 , w, t, x, and y. Homework Equations...

Thanks for the reply. Still that does not answer my question. Let me again rephrase the queston: Let's consider an electric field acting on a H atom. The operator for the force acting on the electron is F(i).e(ri), where i denotes the elecron, ri is the coordinate of electron i, and F(i) is...

Any answer will be greatly appreciated guys. Let me rephrase the question in a different way: Let's consider and external electric field acting on an atom. We know that the field will polarize the electronic cloud and will induce dipole moment in it. How do we proceed to calculate how much...

Hi all. Just have a quick question on perturbation theory. Let's consider a molecule in ground electronic state. If a time-independent external perturbation acts on the molecule, the average electronic energy is going to change. From time-independent perturbation theory, we know that <E> =...

Thanks a ton. Yes I understand that the KE operator still operates on the electronic gradient of the wavefunction. could you please give me a brief idea of how the gradient of KE operator with respect to electronic coordinate is zero. Thanks again.

Hi all. I have a question that I am thinking about for a couple of days. Let's consider the time-independent Schroedinger equation for a molecule: H0 [psi> = E0 [psi> Now, we know that the unperturbed Hamiltonian consist of electronic kinetic energy operator, electron-electron repulsion...

Thanks a lot man. That really helped. Now, is there any way to apply that equation for energy transferred by field to a quantum particle? Can we use the force . displacement equation to get the work done on a quantum system?

Hello everyone. I have been looking for a book or any article where I can get a good description about classical theory of energy transfer from electromagnetic field to a particle. I am particularly interested in how much work is done by the field when it interacts with the partciel (for...

Yeah I was hoping they should be equal. But in the second formula we get terms like <0(1)] H0 [0(1)>, which do not appear in the equation E = E0(0) + E0(1) + E0(2) +..., because E0(2) = <0] V [0(1)>

We all know from time-independent perturbation theory that if we have an atom in ground state [0>, and when a time-independent perturbation acts on it, the energy of the ground state gets shifted and the ground state wave function also gets modified. Using Time-independent Schroedinger eq...

Someone please tell me if I am thinking right: Let's consider an unperturbed electronic state of an atom/molecule. If we denote it by [a>, then the average electronic momentum in state [a> is, <p> = <a]p[a> = (<a]p<a])* (because p is hermitian) = (<a]*p*[a>*)...

I have been using time-dependent perturbation theory for quite a while. Yet, one thing is still not clear to me. I have seen in many books and papers that when they calculate the transition amplitudes, they integrate from 0 to t. While in many other papers and books, the limit is taken to be -...