Comment on ‘‘A multiconfiguration time-dependent Hartree approximation based on natural single-particle states’’ [J. Chem. Phys. 99, 4055 (1993)]

It is shown that the multiconfigurational time-dependent Hartree (MCTDH) equations presented in Jansen’s work are a special case of generalized MCTDH equations presented in earlier work. The convergence with respect to the number of expansion functions employed is unaltered compared to the simple original MCTDH scheme, no reduction in the number of expansion functions required can be gained by employing natural single-particle functions. Also, the computational effort for the numerical integration of the equations of motion is found to be similar for both sets of MCTDH equations.