Research Interests

Multiresolution Analysis

Multiresolution Analysis (MRA) brings an effective way to solve Schrödinger equation.

\[ \hat{H}\Psi=E\Psi \tag{1}\]

It is a real space numerical method used to project functions and operators with arbitrary precision given by the following formula.

\[ f^n (x)= \sum_k \sum_l s^n_{kl} ~ \phi^n_{kl}(x) \tag{2}\]

where \(f^n (x)\) is the function resolved at \(n^{th}\) level, \(\phi^n_{kl}(x)\) are the scaling functions and \(s^n_{kl}\) are the scaling coefficients. The scaling or basis functions are derived from Legendre Polynomials. For a detailed overview, book chapter written by Bischoff [1] is a good starting point. Assuming the potential energy function in the system of interest is \(\hat{V}=V(r)\) and the rearrangement of Equation 1 will give the following expression

\[ (\hat{T} + \hat{V})\Psi = E\Psi \quad \Longleftrightarrow \quad \Psi = -(\hat{T} - E)^{-1}\hat{V}\Psi \quad \Longleftrightarrow \quad \Psi = - G_{\mu} \hat{V} \Psi \tag{3}\]

NoteNote

Point to be noted here is that \(V(r)\) can be any form of potential - Particle in a box, Simple harmonic oscillator, Hydrogen atom, Coulomb and Exchange from Hartree-Fock method etc.

The resulting equation above can be algorithmically considered to be a fixed point iteration problem. It can be self-consistently solved with a given good guess of \(\Psi\). At the end, MRA would produce results in complete basis set (CBS) limit being a real space grid based method.

Molecules in strong magnetic Field

Besides covalent and ionic bonding, there exists a third kind of distinct bonding which occurs primarily in presence of strong magnetic fields. There is a rehybridization of antibonding orbitals in the systems which are non-bonded in ambient atmospheres. For example, singlet He2, it does not have a primary binding interaction according to Molecular Orbital Theory (MOT). But it shows strong primary binding interaction with the increase in \(\mathbf{B}\) values.

References

[1]
F. A. Bischoff, “Computing accurate molecular properties in real space using multiresolution analysis,” vol. 79, Elsevier, 2019, pp. 3–52. Available: https://linkinghub.elsevier.com/retrieve/pii/S006532761930019X