  The accurate prediction and understanding of molecular energy and chemical
reactivity are fundamental pursuits in the field of molecular quantum
chemistry. With the limitations of the current noisy intermediate scale quantum
computer (NISQ) era, the Variational Quantum Eigensolver (VQE) algorithm offers
a promising approach to efficiently estimate the stable energy state of a given
molecule. This study is focused on predicting the ground state and single
electron detachment energy of the hydride ion because of its high electron
electron correlation and numerous applications in astrophysics and quantum
chemistry. The hydride ion is the first three body quantum problem for which
the ground state energy has been calculated theoretically using the
Chandrasekhar Wavefunction, which takes high electron-electron correlation into
account. For the calculation of hydride ion, we used the VQE algorithm with two
types of quantum computational ansatz, (i) chemistry inspired ansatz based on
unitary CC (UCC) and (ii) hardware efficient based ansatz (HEA). To check the
versatility of the algorithm, we analyzed two proton transfer reactions
involving the hydride ion and finds the energy to be exothermic with a much
improved result compared to previous studies. Overall, the VQE algorithm with a
quantum computational approach is found to be reliable in calculating stable
state energy, single electron detachment energy, and reaction energy for proton
transfer reactions involving a highly correlated molecule with a low relative
percentage error.
