Implementation and Application of the Relativistic Equation of Motion
  Coupled-cluster Method for the Excited States of Closed-shell Atomic Systems
  We report the implementation of equation-of-motion coupled-cluster (EOMCC)
method in the four-component relativistic framework with the spherical atomic
potential to generate the excited states from a closed-shell atomic
configuration. This theoretical development will be very useful to carry out
high precision calculations of varieties of atomic properties in many atomic
systems. We employ this method to calculate excitation energies of many
low-lying states in a few Ne-like highly charged ions, such as Cr XV, Fe XVII,
Co XVIII and Ni XIX ions, and compare them against their corresponding
experimental values to demonstrate the accomplishment of the EOMCC
implementation. The considered ions are apt to substantiate accurate inclusion
of the relativistic effects in the evaluation of the atomic properties and are
also interesting for the astrophysical studies. Investigation of the temporal
variation of the fine structure constant (\alpha) from the astrophysical
observations is one of the modern research problems for which we also estimate
the \alpha sensitivity coefficients in the above ions.
