These named lists contain ready-to-use values for all the fundamental physical constants.
Format
A list
, where names correspond to symbols in codata$symbol
.
syms
contains plain numeric values.syms_with_errors
contains objects of typeerrors
, which enables automatic uncertainty propagation.syms_with_units
contains objects of typeunits
, which enables automatic conversion, derivation and simplification.syms_with_quantities
contains objects of typequantities
, which combineserrors
andunits
.
The enriched versions of syms
are available only if the corresponding
optional packages, errors, units and/or quantities are
installed. See the documentation of these packages for further information.
Details
Experimental support for correlations between constants is provided via the errors package, but it is disabled by default. To enable it, the following option must be set before loading the package:
options(constants.correlations=TRUE)
Alternatively, constants:::set_correlations()
may be used
interactively, but scripts should not rely on this non-exported function,
as it may disappear in future versions.
Examples
# the speed of light
syms$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]