In this work, theoretical calculation of the ground and excited state of
coumarin compounds are performed using DFT-B3LYP and CIS methods with
6-31G basis set. IR spectrum, UV/Vis spectrum, molecular orbitals and energy
gap are calculated. We use
different solvents ethanol, methanol, water,
acetonitrile (ACN), dimethyl sulfoxide (DMSO), acetone, and dichloromethane
to compare values of UV/Vis absorption spectra. Then the calculated results are
compared with the experimental values.
In this research, we have done Theoretical study, how to use
perturbation theory in order to obtain approximate solutions of the
time dependent Schrödinger equation.
We also considered application of time dependent perturbation theory to case where the
atomic quantum system interacts with electromagnetic radiation.