addMolecules {Rdisop} | R Documentation

## Add/subtract sum formulae

### Description

Simple arithmetic modifications of sum formulae.

### Usage

    addMolecules(formula1, formula2, elements = NULL, maxisotopes = 10)
    subMolecules(formula1, formula2, elements = NULL, maxisotopes = 10)

### Arguments

`formula1` | Sum formula
`formula2` | Sum formula
`elements` | list of allowed chemical elements, defaults to full periodic system of elements
`maxisotopes` | maximum number of isotopes shown in the resulting molecules

### Details

addMolecules() adds the second argument to the first. subMolecules() subtracts the second argument from the first.

This can be useful to revert e.g. adduct/fragment formation found in ESI mass spectrometry, or to mimick simple chemical reactions. No chemical checks are performed.

### Value

A list with the elements

`formula` | repeated sum formula
`mass` | exact monoisotopic mass of molecule
`score` | dummy value, always 1.0
`isotopes` | a list of isotopes

### Author(s)

Steffen Neumann <sneumann@IPB-Halle.DE>

### Examples

    # For proton-Adduct of Ethanol:
    subMolecules("C2H7O", "H")

[Package Rdisop version 1.52.0 Index]