This dataset consists of shear-mechanical and dielectric data taken
on 7 liquids. 

These data were originally presented in: 
K. Niss and B. Jakobsen, Master thesis in
physics, Department of Mathematics and Physics (IMFUFA), Roskilde
University, 2003. http://dirac.ruc.dk/~kniss/masterthesis

and were later published in:

Bo Jakobsen, Kristine Niss, and Niels Boye Olsen. 
Dielectric and shear mechanical alpha and beta relaxations 
in seven glass-forming liquids. 
Journal of Chemical Physics, 123:234511, 2005.

All experimental information can be found in these references.

This electronic version of the data was published on the
"Glass and time - Data repository" found at http://glass.ruc.dk/data

The authors have copyright to these data. 
The authors have given permission to "Glass and Time" to publish the
data on the "Glass and time - Data repository" web site. 

You are very welcome to use the data for further analysis, but
are requested to cite the original publications whenever use is made of
the data in publications, presentations, etc. 

Any questions regarding the data can be addressed
to boj@ruc.dk or kniss@ruc.dk, who would also appreciate a mail if
you find the data useful.

____________________________________________________________________
The data format is defined as described below:

There is a directory for each sample. The name of the directory
corresponds to the abbreviations used in the original paper (as
defined in table I)

Each directory contains 8 data files.

shearTemp.dat :  temperatures in Kelvin corresponding to shear data. 
dielTemp.dat  :  temperatures in Kelvin corresponding to dielectric data.

Sometimes there might not be the same amount of temperatures, but in 
most cases there is a direct correspondence between the T's of shear
and dielectric. However, in the case of DHIQ, only very few
measurements exist which are taken at the same T. 
The uneven T-steps seen in some cases are due to a temperature
calibration performed after the measurement. Generally the step in T
is 2 degrees.

shearFr.dat  :  the frequencies in Hertz corresponding to the shear data
dielFr.dat   :  the frequencies in Hertz corresponding to the dielectric data

These vectors contain the frequencies. They are approximately
equidistant on a log scale from milli- to mega- hertz.

shearIm.dat   : the imaginary part of the shear modulus in Gpa
shearRe.dat   : the real part of the shear modulus in Gpa
dielIm.dat    : the imaginary part of the dielectric consant
dielRe.dat    : the real part of the dielectric constant

These 4 files contain the data. Each column corresponds to a
temperature; each row corresponds to a frequency. 

For example: shearRe(n,m)+i*shearIm(n,m) is the total complex shear modulus at
temperature shearTemp(m) and frequency shearFr(n) 

If a value in one of the 4 data arrays is 0, it means that no data is
taken at this frequency/temperature.  This is, of course, at the same
points for the imaginary and real part, but not necessarily
simultaneously in shear and dielectric data.

Beside the data files, plots of the data exist as png images for
reference. 

It should be noticed that some noise (notches) exists in the high
frequency part of the shear mechanical data, these are artifacts from
the used HP 4284A LCR meter,  

It should further be noticed that the uncertainty on the absolute
level of the shear-modulus is rather large (up to 20% in worst
case), but the possible error is systematic within one dataset
(liquid). The absolute levels of the dielectric constant are also 
rather large, and here the effect is highly temperature
dependent. In the case of liquids with a small dielectric constant,
the uncertainty of the geometric is the dominant factor determining
the temperature dependence of the absolute levels (see the discussion
in: Niss et al., JCP, 123:234510, 2005).

The measurements of the dielectric constant are rather noisy, for the
substance with low dielectric relaxation strength. In specific, the
change in measurement method at 100Hz is sometimes seen as a shift in
the measured values. 

	   Last edited January 2009, Bo Jakobsen