14/Oct/2002: A copy of the necessary MPQC files is now distributed with
the binary version of Xentark, and extra possible locations are checked at
runtime for these libraries.

9/Nov/2002: Two important new Xentark calculation features have been added
(and the Xykron interface to request and view): calculation of overall
electron density (which is viewed in the same way as orbital spatial
distributions), and the option to use this to determine the partial charge
at each atom. This is based on an algorithm I just made up, so bring your
own grain of salt (!).

4/Jan/2003: New field in the computational resulst to denote whether
convergence occurred during the optimisation.

10/Jan/2003: A new feature for "chaining" computations has been added. Each
CompParams property has a vacancy for specifying the next CompParams
parameter to execute when the current one is done. In this way several
computations can be batched, without having to resort to script files.

25/Jan/2003: Calculation of vibrational frequencies is now implemented.
Unfortunately the underlying libraries do not provide absorption intensity,
but one takes what one can get...

9/Mar/2003: Most of the symmetry elements are now compatible with Xentark.
Some caveats, however, for the present time: (1) the principal axis is
transformed to Z, so to the resulting structure may look slightly
different; (2) rotation axes of order 3 fail, for reasons as yet unknown;
(3) acquisition of spatial coordinates proceeds only within one region of
unique symmetry, so orbital distributions will appear truncated. Also,
Xentark now has some simple integration with Xuru: the "Tick" signifier
will keep the Task information updated, and also paths are updated when
Xentark "chains" to a different set of parameters.

5/Apr/2003: Minor improvement which allows "minimal records" to be kept
during a Xentark computation: if set in the CompParams panel, will cause
only the last cycle to record a CompResults property. This is useful for
some long calculations running under low basis sets, which can operate
through hundreds of cycles, which aren't necessarily very interesting.

22/Jun/2003: A very significant new feature has been added to Xentark: it
now calculates oscillator strengths for particular electronic excitations
(which are said to be qualitatively proportional to the intensity of the
absorption), after determining the eigenvalues. The method used could be
described as ZDO (zero differential overlap; also ignores p & d overlap),
and is quite simple and fast. The transition electric dipole moments for
the excitations are also stored. The significance of this is that it is
the author's first direct use of the underlying wavefunction matrix,
rather than using the MPQC libraries as a "black box" and overlaying
high-level functionality. This is also partly why there have not been very
many mundane improvements to CRK lately. Note that although the results of
this new calculation feature do seem to make sense, only rather
preliminary verification has taken place thus far.

28/Jun/2003: Minor tweak to increase the combinations of oscillator
strengths determined. Some numbers have been compared with results from
Gaussian98, and they appear to be reasonably consistent.

5/Jul/2003: Xentark now calculates partial charges properly, using the
natural atomic orbital populations much are made available by MPQC.
Hydrogen charges are not standardised as zero, however.

20/Jul/2003: Xentark has been modified to submit results while the
calculation is still in progress; this can alleviate some frustrating
delays.
