\title{Initialize (a subset of) elements of the periodic system of
  elements (PSE)}

  Initialize the information about name, mass and isotopes.
  To reduce the number of decomposition hypotheses,
  subsets of elements can be created.

  \item{names}{vector of element names within PSE}

  These functions return full, pre-defined or user-defined (sub-) lists of elements.
  A list with the elements
    repeated sum formula
    exact mass of molecule

	 a list of isotopes 
  The initializeCharges() is special, since it allows to parse charges
	 such as \code{getMolecule("H3O+", elements=c(initializeCHNOPS(),initializeCharges()))}

# For Ethanol:
elements <- initializeCHNOPS()

  For a description of the underlying IMS see:
  WABI Paper

  Isotope patterns obtained through wikipedia.org

\author{Steffen Neumann <sneumann@IPB-Halle.DE>}