  Over the past two decades, some scholars have noticed the correlation between
quantum mechanics and finance/economy, making some novel attempts to introduce
the theoretical framework of quantum mechanics into financial and economic
research, subsequently a new research domain called quantum finance or quantum
economy was set up. In particular, some studies have made their endeavour in
the stock market, utilizing the quantum mechanical paradigm to describe the
movement of stock price. Nevertheless, the majority of researches have paid
attention to describing the motion of a single stock, and drawn an analogy
between the motion of a single stock and a one-dimensional infinite well, or
one-dimensional harmonic oscillator model, whose modality looks alike to the
one-electron Schr\"odinger equation, in which the information is solved
analytically in most cases. Hitherto, the whole stock market system composed of
all stocks and stock indexes have not been discussed. In this paper, the
concept of stock molecular system is first proposed with pioneer. The modality
of stock molecular system resembles the multi-electrons Schr\"odinger equation
with Born-Oppenheimer approximation. Similar to the interaction among all
nuclei and electrons in a molecule, the interaction exist among all stock
indexes and stocks. This paper also establish the stock-index Coulomb
potential, stock-index Coulomb potential, stock-stock Coulomb potential and
stock coulomb correlation terms by statistical theory. At length, the conceive
and feasibility of drawing upon density functional theory (DFT) to solve the
Schr\"odinger equation of stock molecular system are put forward together with
proof, ending up with experiments executed in CSI 300 index system.
