  Spectroscopy is an indispensable tool in understanding the structures and
dynamics of molecular systems. However computational modelling of spectroscopy
is challenging due to the exponential scaling of computational complexity with
system sizes unless drastic approximations are made. Quantum computer could
potentially overcome these classically intractable computational tasks, but
existing approaches using quantum computers to simulate spectroscopy can only
handle isolated and static molecules. In this work we develop a workflow that
combines multi-scale modeling and time-dependent variational quantum algorithm
to compute the linear spectroscopy of systems interacting with their
condensed-phase environment via the relevant time correlation function. We
demonstrate the feasibility of our approach by numerically simulating the
UV-Vis absorption spectra of organic semiconductors. We show that our dynamical
approach captures several spectral features that are otherwise overlooked by
static methods. Our method can be directly used for other linear
condensed-phase spectroscopy and could potentially be extended to nonlinear
multi-dimensional spectroscopy.
