Simulating a Spectrum - the Plot Menu

Once a data file has been created or loaded (File, Open or or simply drag and drop a .pgo file onto the main window) simply press the red simulate button if a simulation does not appear automatically. To change the molecular parameters use the Constants Window. The plot menu entries, many of which are also available as toolbar buttons, can be used to adjust the appearance of the plot. The Offset, rotational temperature (T), and the Gaussian (Gau) and Lorentzian (Lor) contributions to the linewidth can also be changed using the boxes in the main window.

Note: To zoom in on a particular region of the plot, the Plot Selection () button is normally the most useful, with the All button used to zoom out.

The items below are available as buttons on the toolbar or from the plot menu:

Left Shift plot range to left

Right Shift plot range to right

Compress Compress horizontal plot range

Expand Expand horizontal plot range

Plot Selection Click and drag the mouse over part of the spectrum and then press this button to change the horizontal plot range to the selected range. See below to adjust the vertical scale.

All Expand horizontal plot range to include all simulated lines and overlayed spectra. This button is particularly useful if you have "lost" your spectrum.

Simulate Simulate spectrum

Next Plotstyle Cycle through available styles of plot

Show Parts Toggle display of individual spectra making up the overall spectrum

Show Sum Toggle display of sum of individual spectra

Fortrat, Show Toggle display of a Fortrat Diagram

Fortrat, Upper
Select upper or lower state quantum number as vertical axis in Fortrat diagram. It is also possible to adjust the quantum number used; the default is J, but others can be specified by adjusting FortatQno in the Simulation object.

Units Select units for horizontal axis - Possibilities are cm^-1, MHz, Kelvin, eV, velocity (in units of cm^-1/2), nm in vacuum and nm in air.

Magnify from Bottom Reduce vertical range of plot by a factor of two, and turn off automatic upper limit. The lower limit of the plot is left unchanged. This only affects the overlay scaling, unless no overlays are displayed, in which case the scaling of the simulation is changed. For more control, see AutoMin, AutoMax, Ymin and Ymax in the Simulation and Plot objects.

Magnify from Top Reduce vertical range of plot by a factor of two, and turn off automatic lower limit. The upper limit of the plot is left unchanged. This only affects the overlay scaling, unless no overlays are displayed, in which case the scaling of the simulation is changed. For more control, see AutoMin, AutoMax, Ymin and Ymax in the Simulation and Plot objects.

Auto Vertical Scale
Toggle automatic vertical scaling. This only affects the overlay scaling, unless no overlays are displayed, in which case the scaling of the simulation is changed. For more control, see AutoMin, AutoMax, Ymin and Ymax in the Simulation and Plot objects.

Plot Options,
Styles...
This enables the colour, the width of the lines and the line style of spectra to be changed. To alter one of these settings, select the relevant tick box, click "Apply", alter as required, and click "OK". The changes will be effected on re-simulating the spectrum. Selecting "Default" restores spectra to solid, zero width lines. (Colours of spectral lines are best changed in the constants window.)

Plot Options,
Font Select font for plots.

Plot Options,
Variable Char Size
Select (default) for character size on printout, clipboard and export to reflect on screen proportions. If not selected the character size remains fixed.

Plot Options,
Limit Line Segments Select (default) to limit number of segments on a plotted curve. It can be helpful to unselect this option if you intend to edit exported plots. The only drawback is that the resulting plots can be too complicated for some programs to handle.

Magnify Plot Click and drag with the mouse to select a region to zoom into with this button. In contrast to Plot Selection and other buttons above, this changes both the vertical and horizontal scale, and the scaling is reset when the plot is updated.

Shrink plot Shrink plot in both vertical and horizontal scale.

Reset Zoom Reset plot zoom to fill window. This happens implicitly when the plot is updated.

	Left	Shift plot range to left
	Right	Shift plot range to right
	Compress	Compress horizontal plot range
	Expand	Expand horizontal plot range
	Plot Selection	Click and drag the mouse over part of the spectrum and then press this button to change the horizontal plot range to the selected range. See below to adjust the vertical scale.
	All	Expand horizontal plot range to include all simulated lines and overlayed spectra. This button is particularly useful if you have "lost" your spectrum.
	Simulate	Simulate spectrum
	Next Plotstyle	Cycle through available styles of plot
	Show Parts	Toggle display of individual spectra making up the overall spectrum
	Show Sum	Toggle display of sum of individual spectra
	Fortrat, Show	Toggle display of a Fortrat Diagram
	Fortrat, Upper	Select upper or lower state quantum number as vertical axis in Fortrat diagram. It is also possible to adjust the quantum number used; the default is J, but others can be specified by adjusting FortatQno in the Simulation object.
	Units	Select units for horizontal axis - Possibilities are cm^-1, MHz, Kelvin, eV, velocity (in units of cm^-1/2), nm in vacuum and nm in air.
	Magnify from Bottom	Reduce vertical range of plot by a factor of two, and turn off automatic upper limit. The lower limit of the plot is left unchanged. This only affects the overlay scaling, unless no overlays are displayed, in which case the scaling of the simulation is changed. For more control, see AutoMin, AutoMax, Ymin and Ymax in the Simulation and Plot objects.
	Magnify from Top	Reduce vertical range of plot by a factor of two, and turn off automatic lower limit. The upper limit of the plot is left unchanged. This only affects the overlay scaling, unless no overlays are displayed, in which case the scaling of the simulation is changed. For more control, see AutoMin, AutoMax, Ymin and Ymax in the Simulation and Plot objects.
	Auto Vertical Scale	Toggle automatic vertical scaling. This only affects the overlay scaling, unless no overlays are displayed, in which case the scaling of the simulation is changed. For more control, see AutoMin, AutoMax, Ymin and Ymax in the Simulation and Plot objects.
	Plot Options, Styles...	This enables the colour, the width of the lines and the line style of spectra to be changed. To alter one of these settings, select the relevant tick box, click "Apply", alter as required, and click "OK". The changes will be effected on re-simulating the spectrum. Selecting "Default" restores spectra to solid, zero width lines. (Colours of spectral lines are best changed in the constants window.)
	Plot Options, Font	Select font for plots.
	Plot Options, Variable Char Size	Select (default) for character size on printout, clipboard and export to reflect on screen proportions. If not selected the character size remains fixed.
	Plot Options, Limit Line Segments	Select (default) to limit number of segments on a plotted curve. It can be helpful to unselect this option if you intend to edit exported plots. The only drawback is that the resulting plots can be too complicated for some programs to handle.
	Magnify Plot	Click and drag with the mouse to select a region to zoom into with this button. In contrast to Plot Selection and other buttons above, this changes both the vertical and horizontal scale, and the scaling is reset when the plot is updated.
	Shrink plot	Shrink plot in both vertical and horizontal scale.
	Reset Zoom	Reset plot zoom to fill window. This happens implicitly when the plot is updated.