  This is the first in a series of articles in which we study the rotating
Morse potential model for diatomic molecules in the tridiagonal J-matrix
representation. Here, we compute the bound states energy spectrum by
diagonalizing the finite dimensional Hamiltonian matrix of H2, LiH, HCl and CO
molecules for arbitrary angular momentum. The calculation was performed using
the J-matrix basis that supports a tridiagonal matrix representation for the
reference Hamiltonian. Our results for these diatomic molecules have been
compared with available numerical data satisfactorily. The proposed method is
handy, very efficient, and it enhances accuracy by combining analytic power
with a convergent and stable numerical technique.
