Objects Mixture  <Prev Next> 
IntensityUnits  Units for intensity. These are described in detail under Intensity Formulae.
Possible values are:
Misleading results can be obtained for a setting of Arbitrary when simulating isotopologues or isotopomers with different symmetry or statistical weights together, such as ^{35}Cl_{2} and ^{35}Cl^{37}Cl. The calculation is "correct", in that the partition function is necessary to give the correct relative intensities, but is excluded by design for this setting. 
LifeModel  Model to use for state dependent lifetimes and linewidths.
Valid values are lmNone, lmWidth, lmProduct, lmProductWidth,
lmParent, lmParentWidth, lmGate, lmGateWidth. See Widths and Lifetime Effects for how
this setting works. 
PlotUnits  Units for the horizontal scale for spectrum plots.
Possibilities are standard energy units (cm1, MHz,
Kelvin and eV) as in the Mixture object and also:

Fluorescence  Set to always discard lower state population; see Emission Spectra for further discussion of this flag. 
nDF  Number of points (between Fmin and Fmax) to calculate the spectrum at. Note that if a peak width is less than 3*(FmaxFmin)/nDF, i.e. only a few points wide, then it is shown as a stick, rather than a peak. 
WidthMult  Multiple of line width to extend convolution over. 
AutoMin  If set (the default), Ymin is automatically updated to minimum point in plot range 
AutoMax  If set (the default), Ymax is automatically updated to maximum point in plot range 
ShowSum  Plot overall sum of individual spectra. This is toggled by the button. 
ShowParts  Plot individual spectra making up overall spectrum. The individual spectra are grouped by colour, so you will need to set colours to see something different to the sum. Colours can be set at the transition moment, state, molecule or species level. This is toggled by the button. 
ShowFortrat  Plot a Fortrat diagram, i.e. J against frequency, in the main window. This is toggled by the button. 
UseUpper  Set to use upper rather than lower state J and symmetry in the Fortrat diagram. 
ShowSymmetry  Show symmetry in Fortrat plots. 
ShowDeltaJ  Show change in J in Fortrat plots. 
ScaleMarkSize  Scale Mark Size with intensity in Fortrat plots. 
UseSymmetry  If true, show different symmetries in separate Fortrat plots. 
UseStateNumber  If true, show different state numbers in separate Fortrat plots. 
FortratQno  Select quantum number to use in Fortrat plots. 
PreserveArea  If set, then changing the PlotUnits
changes the vertical scale, giving a constant area to peaks.
This implies the units of the vertical scale depend on the
horizontal scale. For example, if units of cm2WavenumberperMolecule
are selected for IntensityUnits and the PlotUnits
are MHz the vertical scale units are actually cm^{2}wavenumber/molecule/MHz
to give integrated peak areas (calculated from the numerical
values plotted) of cm^{2}wavenumber/molecule
independent of the PlotUnits. Versions of PGOPHER
before 10.1 did this by default. The default in newer versions is to not set this parameter, and thus always plot the same quantity for intensity. Changing the PlotUnits thus does not change the vertical scale, which is less confusing when comparing to experimental spectra or doing contour fits. 
SeparateScales  When showing multiple plots, scale plots
separately, rather than requiring the same scale factor for
each. 
LogScale  Take ln of vertical axis on plots. (Initial
implementation.) 
Show2DPlot  (Future Use) 
Auto2DY  (Future Use) 
Fmin  Left edge of plot range in main window. 
Fmax  Right edge of plot range in main window. 
Ymin 
Lower end of current plot
range; overwritten with lowest value in current range if AutoMin set 
Ymax  Upper end of current plot range; overwritten with lowest value in current range if AutoMin set 
Temperature  Rotational temperature (Kelvin). Setting this < 0 will force the use of numerical populations for all manifolds, as described in NonBoltzmann Populations. 
Gaussian  Gaussian contribution to linewidth (full width half
maximum). If both this and a Lorentzian width (below) is set
the result is a convolution of the two, a Voigt profile.
Note that this is in PlotUnits, and is taken to be
constant over the plot range, which may be a concern if the
plot range is large, as a width that is constant in
wavelength will not be constant in frequency. 
Lorentzian  Lorentzian contribution to linewidth (full width half maximum). This and the Gaussian width can also be set from the main window. Note that this is in PlotUnits, and is taken to be constant over the plot range, which may be a concern if the plot range is large, as a width that is constant in wavelength will not be constant in frequency. 
Foffset  Frequency offset to simulation. 
SMargin  This setting controls the number of extra points to
calculate at each end of the spectrum. (These points are not
plotted, but may be required to avoid artefacts in the
convoluted spectrum): If > 0: Number of extra points to calculate at each end If < 0: Number of points is SMargin*WidthMult*(Gaussian+Lorentzian) 
OThreshold  Ignore peaks smaller than this fraction of the maximum
peak intensity in selected simulations. In line listings,
lines with an intensity less than this are excluded from the
printout; in this case the value is absolute, rather than a
fraction of the strongest. Note that line lists produced by
File, Export, Line List use a separate value that is a
fraction of the maximum intensity. 
RefWidth  Reference width in linewidth (predissociation)
calculations; see LifeModel 
Tvib  Vibrational Temperature (Kelvin); set to 1 (default) to use rotational temperature for all Boltzmann factors. 
MinI  Discard lines weaker then this fraction of the strongest
in Fortrat plots. Note that the default for this increased
from 0 to 0.01 in 10.0.31. 
Saturation  Zero for normal calculation; positive values progressively
switch strength to population only by replacing the line
strength, S by: S = (1exp(S*Saturation/g))*g
where g = Min(2J'+1, 2J"+1)*Statistical
Weight. This is appropriate for saturation by z polarized light.
Values of, say, 1 to 10 will wash out the differences
between allowed branches and much higher values will bring
out transitions that are only allowed by some weak mixing. 
Tspin 
Spin temperature (Kelvin); set to 1 (default) to assume
equilibrated nuclear spin states. If set >=0 then the
fraction of molecules with each particular nuclear spin
species (ortho/para for diatomics) is fixed at the
fractions found at T = Tspin. This is often appropriate
for molecular beams, where the nuclear spin states do not
relax during the expansion. There are two limitations in
the current implementation, which may lead to incorrect
results:

IScale  Scale all simulated intensities by this
value. (The default is 1.) 
EField  Static electric field, V/m;
see External Fields  The Zeeman
and Stark Effects 
BField  Static magnetic field in Tesla (= 10^{4} Gauss); see External Fields  The Zeeman and Stark Effects 
Doppler 
Plot each transition as two peaks, split by 2*Doppler*Centre Frequency. This gives the double peak structure often seen in Fourier transform microwave spectroscopy. 
PlotSplit 
Fraction of plot area to use for the
simulation where simulation and overlay plots are separated.
The possible range is 1..1, with 0.5 the default. Negative
values put the simulation, rather than the overlay, at the
top. 
Ymin2D  (Future Use) 
Ymax2D  (Future Use) 
Right click on the item in the constants
window for the following operations in addition to the
standard ones: