sw_readspec

Syntax

data = sw_readspec(datapath)

Description

data = sw_readspec(datapath) reads experimental spin wave dispersion data from a text file at the given location. The general format of the data file is described in sw_readtable with sw_readspec requires predefined header names and only specific tag strings are allowed. The following header line is required:

QH QK QL minE maxE I1 E1 s1 I2 E2 s2 ...

where:

• QH $h$ index of the $Q$ point in rlu,
• QK $k$ index of the $Q$ point in rlu,
• QL $l$ index of the $Q$ point in rlu,
• minE lower boundary of the $E$ scan,
• maxE upper boundary of the $E$ scan,
• In intensity of the $n$th spin wave mode,
• En center of the $n$th spin wave mode, has to be in increasing order,
• sn standard deviation of the corresponding energy

The number of modes in a single line of the data file is unlimited, however in every line the number of modes have to be the same. Rows with less modes should contain zero intensities at the position of the missing modes.

Before any data line a special tag line can be inserted that gives the measured correlation in square brackets, for axample: '[Mxx+Myy]'. For the formatting of this string, see sw_parstr. If the measured type of correlation is undefined, unpolarised neutron scattering intensity is assumed (equivalent to 'Sperp'). When cross sections measured in the Blume-Maleev coordinate system, see sw_egrid, the normal to the scattering plane has to be also defined. This can be given in a second pair of square brackes in the $xyz$ coordinate system, for example: '[Myy] [1 0 0]'. If $n$ is undefined, the default value is '[0 0 1]'.

Examples

Example input data file (polarised scans in the $(0,k,l)$ scattering plane):

QH    QK        QL      ENlim1  ENlim2  I1  EN1       s1    I2  EN2       s2
[Mxx] [1 0 0]
0     1        2.9992   0       15      1    3.7128   1.0   1   8.6778    1.0
0     1        2.8993   0       15      1    7.0000   1.0   1   11.1249   1.0
0     1        2.7993   0       20      1   13.8576   1.0   0   0.0       0.0
0     1        2.6994   0       20      1   17.3861   1.0   0   0.0       0.0
[Myy] [1 0 0]
0     1.0000   2.0000   0       25      1   20.2183   1.0   0   0.0       0.0
0     1.1000   2.0000   15      30      1   22.7032   1.0   0   0.0       0.0
0     1.2000   2.0000   20      35      1   25.1516   1.0   0   0.0       0.0

See Also

sw_egrid | spinw.fitspec