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Lists of Constants

Source: R/constants.R
syms.Rd

These named lists contain ready-to-use values for all the fundamental physical constants.

Usage

syms

syms_with_errors

syms_with_units

syms_with_quantities

Format

A list, where names correspond to symbols in codata$symbol.

  • syms contains plain numeric values.

  • syms_with_errors contains objects of type errors, which enables automatic uncertainty propagation.

  • syms_with_units contains objects of type units, which enables automatic conversion, derivation and simplification.

  • syms_with_quantities contains objects of type quantities, which combines errors and units.

The enriched versions of syms are available only if the corresponding optional packages, errors, units and/or quantities are installed. See the documentation of these packages for further information.

Details

Experimental support for correlations between constants is provided via the errors package, but it is disabled by default. To enable it, the following option must be set before loading the package:

options(constants.correlations=TRUE)

Alternatively, constants:::set_correlations() may be used interactively, but scripts should not rely on this non-exported function, as it may disappear in future versions.

See also

codata, lookup.

Examples

# the speed of light
syms$c0
#> [1] 299792458
# use the constants in a local environment
with(syms, c0)
#> [1] 299792458

# attach only Planck-related constants
(lkp <- lookup("planck", ignore.case=TRUE))
#>        symbol                                  quantity
#> 138       nah                     molar Planck constant
#> 199         h                           Planck constant
#> 200       hev                  Planck constant in eV/Hz
#> 201      plkl                             Planck length
#> 202      plkm                               Planck mass
#> 203 plkmc2gev      Planck mass energy equivalent in GeV
#> 204    plktmp                        Planck temperature
#> 205      plkt                               Planck time
#> 231      hbar                   reduced Planck constant
#> 232    hbarev           reduced Planck constant in eV s
#> 233   hbcmevf reduced Planck constant times c in MeV fm
#>                          type        value uncertainty     unit
#> 138          Physico-chemical 3.990313e-10     0.0e+00 J/Hz/mol
#> 199 Universal, Adopted values 6.626070e-34     0.0e+00     J/Hz
#> 200                 Universal 4.135668e-15     0.0e+00    eV/Hz
#> 201                 Universal 1.616255e-35     1.8e-40        m
#> 202                 Universal 2.176434e-08     2.4e-13       kg
#> 203                 Universal 1.220890e+19     1.4e+14      GeV
#> 204                 Universal 1.416784e+32     1.6e+27        K
#> 205                 Universal 5.391247e-44     6.0e-49        s
#> 231 Universal, Adopted values 1.054572e-34     0.0e+00      J*s
#> 232                 Universal 6.582120e-16     0.0e+00     eV*s
#> 233   Universal, Non-SI units 1.973270e+02     0.0e+00   MeV*fm
idx <- as.integer(rownames(lkp))
attach(syms[idx])
h
#> [1] 6.62607e-34
plkl
#> [1] 1.616255e-35

# the same with uncertainty
detach(syms[idx])
attach(syms_with_errors[idx])
h
#> 6.62607(0)e-34
plkl
#> 1.61626(2)e-35

# the same with units
detach(syms_with_errors[idx])
attach(syms_with_units[idx])
h
#> 6.62607e-34 [J/Hz]
plkl
#> 1.616255e-35 [m]

# the same with everything
detach(syms_with_units[idx])
attach(syms_with_quantities[idx])
h
#> 6.62607(0)e-34 [J/Hz]
plkl
#> 1.61626(2)e-35 [m]