#Igor pro wavemetrics full

This data set is best handled using a smoothing factor of 1: In particular, if your peaks are narrow, you may need to reduce the smoothing factor. You get access to the settings by clicking the arrow in the Locate Peaks box: If the fully automatic peak finder does not work for your data, you may be able to get better results by adjusting parameters used by the auto peak finder algorithm. The algorithm tries to guess the noise level of your data and, most critically, an optimum smoothing factor used on the second derivative of the data. This invokes an automatic peak-finding algorithm that searches for peaks by finding maxima in the smoothed second derivative of the data. Usually you will start the analysis of a data set by clicking the button labelled 'Auto-locate Peaks Now'. You can enter values numerically, use the auto peak finder, interactively draw or edit your peaks with the mouse or some combination of these methods. The initial values for the fit, i.e., the number, placement and properties of the peaks, can be set in several ways. If you cannot find an appropriate peak type or baseline function, you can extend the package by writing your own functions in Igor's internal language. The Multi-peak Fit package has peak types and baseline functions that will answer most needs. However, especially in cases where there is a clear distinction between baseline and peaks, you can use any other Igor capabilities to subtract out the baseline before the fit. In general, it is much better to fit with a baseline function than to try to remove the baseline from the data and then fit. The package supports a variety of baseline functions, including none, a simple vertical offset, linear, and cubic polynomial. The three asymmetric peak shapes can be useful in fitting chromatographic data. A Voigt is often used in spectroscopic and X-ray work.ĮxpModGauss is the convolution between a Gaussian and an exponential decay while ExpConvExp is the convolution of two exponential decays. A shape factor of zero is pure Gaussian with the Lorentzian contribution increasing as shape increases. It includes a shape parameter that adjusts the relative contribution of the two. All the peaks except LogNormal have their location parameter set at zero.Ī Voigt is the convolution between a Gaussian and a Lorentzian.

#Igor pro wavemetrics full

The various peak types shown here (except LogNormal) have been adjusted to have the same Full Width at Half Max.

The following graph illustrates the different types:

You can use any mix of these peak types while fitting a single data set. The ExpModGauss function is also known as Exponentially Modified Gaussian. This package can fit multiple overlapping peaks using any of six basic peak fit types: Gaussian, Lorentzian, Voigt, ExpModGauss, ExpConvExp and LogNormal. Note: fitting to overlapping peaks has often been called 'deconvolution.' This is not strictly correct as the peaks are merely added together and not convolved in the mathematical sense. In the result shown above the residuals are just noise indicating a good fit. The residuals plot (at the top in the graph above) is very handy in deciding whether the fit is good or whether there may be additional peaks lurking in the data.

Individual peaks, the overall fit trace and baseline are included on the graph. You can have as many different graphs and data sets under analysis simultaneously as you want since each graph has its own control panel. This control panel controls most aspects of choosing peak types and generating initial guesses. When you click Continue, the result is a graph with an associated control panel 'stuck' to the graph. In the resulting control panel, choose your x and y data. To start, you select Start New Multi-peak Fit from the Analysis menu. Support for Igor programmers to do batch peak fitting.Support for Igor programmers to use the fitting engine.Write your own peak and baseline functions.even when there is no analytic expression. Location, FWHM, peak height, and area for fitted peaks.Mix different peak types in a single fit.Fit six different peak types provided with the package.Work on multiple data sets simultaneously.Fit any number of peaks in one data set.This package, like many others included with Igor, can be accessed simply by choosing a menu item. If you have spectroscopic, chromatographic or other forms of data containing multiple, often overlapping peaks, you will appreciate Igor Pro®'s multi-peak fitting package. Wide-Angle Neutron Spin Echo Spectroscopy.