  The article considers the successful implementation of relativistic
equation-of-motion coupled cluster method for the electron attachment problem
(EA-EOMCC) at the level of single- and double- excitation approximation. The
implemented relativistic EA-EOMCC method is employed to calculate ionization
potential values of alkali metal atoms (Li, Na, K, Rb, Cs, Fr) and the vertical
electron affinity values of LiX (X = H, F, Cl, Br), NaY (Y = H, F, Cl) starting
from their closed-shell configuration. Both four-component and exact
two-component calculations are done for all the opted systems. Further, we have
shown the effect of spin-orbit interaction considering the atomic systems. The
results of our atomic calculations are compared with the values from the NIST
database and the results are found to be very accurate (< 1 %).
