Simulation of quantum chemistry is one of the killer applications of quantum computers. In recent years, Google, IBM and other IT companies have been engineering increasingly good superconducting qubits for the purpose of simulating molecular structures. In the beginning, the quantum phase estimation algorithm was considered for obtaining the ground-state energies of molecules. However, the scalability of such a quantum algorithm is too demanding for current quantum technology. An alternative method is the “variational eigensolver,” which can be applied to construct a unitary version of the coupled-cluster ansatz, resolving one of the major obstacles in classical quantum chemistry. However, variational eigensolvers can only provide a means to obtain the electronic structure of molecules. For a comparison with the experimental data, quantum computers should be able to predict the spectra of the molecules.