4.2 The potential energy in a MOFSET device near the metal oxide interface is approximately V(x) ...
2. Variational method. We can approximate the true ground-state wavefunction of the harmonic -프sxs and w(x) =D0 cos(cx) in the range oscillator by the trial wavefunction p(x) = X 2c 2c outside this range. (This wavefunction is already normalized). (A) Compute the energy expectation value of b as a function of c. (B) Determine the value of c that gives the minimal energy. (C) Compare the minimal energy to the energy of the true ground-state wavefunction 2. Variational method. We...
2. The unational method is an incredibly simple but surprisingly powerful method for understanding the low- energy behavior of quantu systems. It is used constantly in marny-body physics and in quantum chemistry. The main idea is thst for any physical Hamiltonian, there is a lowest energy state, i.e. the ground state Ipo). All other states (ignoring degeneracy) have higher energy that this one. Therefore we have Therefore, to get an upper bound on the energy of Eo, it suffices to...
Estimate the ground-state energy of a one-dimensional simple harmonic oscillator using (50) = e-a-l as a trial function with a to be varied. For a simple harmonic oscillator we have H + jmwºr? Recall that, for the variational method, the trial function (HO) gives an expectation value of H such that (016) > Eo, where Eo is the ground state energy. You may use: n! dH() ||= TH(c) – z[1 – H(r)], 8(2), dx S." arcade an+1 where (x) and...
Questions 3-5 3. The predecessor to Hartree-Fock was the Hartree method, where the main difference is that the Hartree-Fock method includes an trial wavefunction by writing it as a Slater Determinant, while the Hartree method uses a simple product wavefunction that does not capture anti- symmetry. In particular, for a minimal-basis model of, the Hartree method's trial wavefunction is given in the while the Hartree-Fock trial wav is given by where and are molecular orbitals, and and coordinates of electron...
Quantum Mechanics II Consider the linear potential V = al.]. Use a Gaussian = exp(-Bx?) as the trial wave function, and calculate the ground state energy with the variational principle. De- termine the parameter B which minimizes the energy, and find Emin Express Emin = f x (hop/2m)1/3, and give the numerical value of the factor f. This is the upper bound of the true ground state energy, E Compare Emin with the exact result, E. = 1.019 (1?o?/2m)/3, and...
2. Consider an electron in a 1D potential box (V(x) = 0 for 0<x<L, V(x) = co otherwise) of length L = 1 nm. The electron is described by the wave function, c) = Jasin ( (a) Using the appropriate Hamiltonian derive an expression for the kinetic energy of the electron (5 marks) (b) Calculate the energy (in Joules) of the transition between the ground state and the 1 excited state. [3 marks]
1. Consider a 1D finite square well potential defined as follows. Vo-a<x<a V(x) = 0otherwise a) What are the energy eigenfunctions n of the Hamiltonian for a single particle bound in this potential? You may write your answer in piece-wise form, with an arbitrary normalization. b) Derive the characteristic equation that the energy eigenvalues E, must satisfy in order to satisfy the eigenvalue equation Hy,-EnUn for eigen function Un c) Write a computer program1 to find the eigenvalues E, for...