Constants
The following mathematical and physical constants are available through the h
module:
h.PI 3.14159265358979323846
h.E 2.71828182845904523536
h.GAMMA 0.57721566490153286060 (Euler)
h.DEG 57.29577951308232087680 (deg/radian)
h.PHI 1.61803398874989484820 (golden ratio)
h.FARADAY 96485.3321233100141 (modern value. derived from mole and electron charge)
h.R 8.3144626181532395 (modern value. derived from boltzmann constant and mole)
h.Avogadro_constant 6.02214076e23 (codata2018 value, introduced version 8.0)
As of Version 8.0 (circa October, 2020) modern units are the default.
Warning
Constants are not treated specially by the interpreter and
may be changed with assignment statements. However a change of
FARADAY
, R
, or Avogadro_constant
generate a warning message
(default once).
Python warning messages can be managed with
import warnings; warnings.filterwarnings(action)
where useful actions
are "error"
, "ignore"
, "always"
, or "once"
.
If assignment takes
place due to execution of a hoc interpreter statement, the warning occurs
only once but cannot be avoided.