# Class "spec" for the storage of spectral models.

### Description

`spec`

is the class for spectral models;
an object
of class "mass" is initialized if
`mod_type = "spec"`

is an
argument of `initModel`

.
All objects of class
`spec`

are
also of class `dat`

; see documentation for `dat`

for a description of
these slots. Note that here `x2`

will refer to the independent variable in
which traces are resolved, e.g., wavelength or wavenumber.

### Objects from the Class

Objects can be created by calls of the form `new("spec", ...)`

or
`spec(...)`

.

### Slots

`clpequ`

:Object of class

`"vector"`

of starting values for linear relationships between clp`specpar`

:Object of class

`"list"`

of vectors of starting values for spectral parameters; the number of vectors gives the number of components in the resulting spectral model; each vector contains the parameters associated with a component. e.g.,`specpar = list(c(20000, 3000, .3, 21000, 2000, .4), c(18000, 1000, .2))`

; the parameters in each vector are grouped`c(location_spectra, width_spectra, skew_spectra)`

. the location and width parameters are given in wavenumbers.`specfun`

:Object of class

`"character"`

,`"gaus"`

for a spectral model of a superposition of skewed Gaussians;`"bspline"`

for a bspline-based model.`specref`

:Object of class

`"numeric"`

index defining the center value of the`x2`

variable.`specCon`

:Object of class

`"list"`

used internally to store constraints.`specdisp`

:Object of class

`"logical"`

`TRUE`

if time-dependence of the spectral parameters is to be taken into account and`FALSE`

otherwise`specdisppar`

:Object of class

`"list"`

`specdispindex`

:Object of class

`"list"`

of vectors defining those indexes of specpar whose time-dependence is to be modeled. e.g.,`specdispindex = list(c(1,1), c(1,2), c(1,3))`

says that parameters 1-3 of spectra 1 are to be modeled as time-dependent.`nupow`

:Object of class

`"numeric"`

describing the power to which wavenumbers are raised in the model equation; see Equation 30 of the paper in the references section for a complete description`timedep`

:Object of class

`"logical"`

describing whether the model for spectra E is dependent on x-index (i.e., whether it is clp-dependent).`parmufunc`

:Object of class

`"character"`

describing the function form of the time-dependence of spectral parameters; options are`"exp"`

for exponential time dependence,`"multiexp"`

for multiexponential time dependence, and`"poly"`

for polynomial time dependence. defaults to polynomial time dependence.- ncole
vector describing the number of columns of the E matrix for each value in the

`x`

vector

### Extends

Class `dat-class`

, directly.

### Author(s)

Katharine M. Mullen, Ivo H. M. van Stokkum

### References

Ivo H. M. van Stokkum, "Global and target analysis of time-resolved spectra, Lecture notes for the Troisieme Cycle de la Physique en Suisse Romande", Department of Physics and Astronomy, Faculty of Sciences, Vrije Universiteit, Amsterdam, The Netherlands, 2005, http://www.nat.vu.nl/~ivo/pub/2005/lecturenotes3cycle.pdf

### See Also

`kin-class`

,
`dat-class`