Bethe Ansatz and Rogers-Ramanujan-type identities

The Rogers-Ramanujan identity for $\text{\hspace{0.17em}⁣}\text{\hspace{0.17em}⁣}{\phantom{\mathrm{\mid }}}_1{\psi }_1$ $$\sum _{n\in \mathbb{Z}}\frac{(a;q{)}_n}{(b;q{)}_n}{z}^n=\frac{(q,b\mathrm{/}a,az,q\mathrm{/}az;q{)}_{\mathrm{\infty }}}{(b,q\mathrm{/}a,z,b\mathrm{/}az;q{)}_{\mathrm{\infty }}}$$ can be classified as one related to the Bethe Ansatz for ``chain length $N=1$, ground state XXZ model with an arbitrary negative spin’'.