Dear Colleagues

With this letter we inform you about the availability of the
Heidelberg MCTDH package. The multiconfiguration time-dependent
Hartree (MCTDH) algorithm has proven its power for solving
multi-dimensional quantum dynamics problems trough several
applications. (See, e.g. the list of MCTDH publications
http://www.pci.uni-heidelberg.de/tc/usr/mctdh/ref.html).
However, the MCTDH algorithm is rather complicated and not
everybody would like to invest in writing his own MCTDH code.
We therefore had decided to make the Heidelberg MCTDH package
available to interested researchers. We also tried to make the
use of the complicated MCTDH algorithm as simple as possible.

MCTDH is a powerful algorithm designed to solve quantum molecular
dynamics of relatively large systems. The full power of MCTDH becomes
obvious when turning to systems the primitive product grid of which
ceases to fit into the memory. (The largest primitive product grid
we had worked with consisted of 4.0E+39 points!)
However, The Heidelberg MCTDH package is also very useful for solving
comparatively small systems. It has been successfully applied to
various 3D problems. In fact, the Heidelberg MCTDH package has been
used even to solve 1D and 2D problems, because it provides a
convenient set of analyze and visualization tools linked to the
propagation program. Some people use MCTDH in their lectures to show
their students, how a wavepacket evolves.

Several groups have used or are using the Heidelberg MCTDH package
in their research. To give you an impression, I list some of them:

O. Kuehn, FU Berlin, Germany
B. Pouilly, S. Briquez, Lille, France
Chr. Iung, F. Gatti, Montpellier, France
H. Koeppel, Heidelberg, Germany
M. Desouter-Lecomte, Orsay, France
C. W. McCurdy, Berkeley, USA
T. Martinez, University of Illinois, USA
P. Rosmus, Marne la Vallee, France
G. A. Worth, Birmingham, UK
R. van Harrevelt, TU Munich, Germany
M. Nest, P. Saalfrank, Potsdam, Germany
G.-J. Kroes, Leiden, Netherlands
V. May, HU Berlin, Germany


The Heidelberg MCTDH package is a set of programs for
multi-dimensional quantum dynamics, and can do much more than
wavefunction (or density operator) propagation using the MCTDH
algorithm. For example, numerically exact propagations are also
possible as well as the computation of eigen-energies and the
generation of eigen-functions.

The package consists of 50 programs,
the largest and most important of which is called simply 'mctdh'.
Using keyword input read from text files, it is able to set up a
system using a range of DVRs or FFT for the primitive basis,
form an initial wavefunction (density operator), and propagate
this wavefunction (density operator) in time.
Perhaps one of the most powerful features of the program is that it
uses a text input to generate the operator. In fact, if the operator
has a simple analytic form, it is often possible to implement it
without having to touch the code. Routines coding for more complicated
functions can also be linked to the program. If potential functions
are not in the product form, which is required by the Heidelberg
MCTDH package, there is the 'potfit' program to transform a potential
to product form. Time-dependent Hamiltonians can also be used.

Other important programs of the package are a set of analysis tools.
These include 'filter', which performs a filter analysis of
the autocorrelation function, and 'flux', which does the flux analysis.
Various programs plot one- and two-dimensional graphs of the
wavefunction and the potential energy surface, and simple movies can
be made. Other programs can be used to check the convergence of a
calculation, generate a spectrum from the autocorrelation function,
etc. All plotting uses the freely available Gnuplot program, often
driven using interactive menus.

The package consists of more than 250,000 lines, of which 190,000
lines are FORTRAN 77 code. There is also some C code, and a number of
bash scripts. The documentation consists of both on-line documentation
(in HTML) and the MCTDH User's Guide (in LaTeX). The installation
is performed by convenient installation scripts. We have run MCTDH on
DEC-alpha, IBM-RS6000, Cray, Sun, Silicon Graphics and HP computers,
and in particular on Linux-PC's.


The Heidelberg MCTDH package is available to interested researchers.
For more details see:
http://www.pci.uni-heidelberg.de/tc/usr/mctdh/

To request the package, please sent an e-mail to
[log in to unmask]

Before requesting the package, please visit the MCTDH web site and check
whether MCTDH is suitable for solving your scientific problem.
Note that MCTDH is not a quantum chemistry package.

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