A Hybrid Quantum Computing Method for UV–Vis Spectroscopy of Solvated Molecules at Room Temperature

We developed a method to include solvent effects on electronic transition calculations using quantum computing, employing the subspace-search variational quantum eigensolver (SSVQE) algorithm and the average solvent electrostatic configuration (ASEC) model. The SSVQE algorithm is used to calculate the energy of ground and excited states of organic molecules, and the ASEC model is used to describe the electrostatic contribution of the solvent effect at room temperature. By comparing the results with complete active space configuration interaction calculations, we demonstrate that the solvent effect is properly accounted for in the calculation of each state energy value performed by the quantum algorithm. Furthermore, the gas-liquid shift of the electronic transitions is also correctly described, with values that present semiquantitative agreement with results obtained through more sophisticated treatment using classical computers and experimental values, demonstrating that the solvation model is robust even when paired with quantum algorithms. The ASEC-SSVQE method opens the possibility of using noisy intermediate-scale quantum devices to study the spectroscopy properties of solvated molecules, with the inclusion of thermodynamic effects.