Use CODATA 2022 for physical constants

ChangeLog.rst

@@ -32,6 +32,10 @@ Modified:
 * Fix typos in uncertainties in the neutron table (Zr-90, Te-124, Ba-138, Sm-147)
 * Use correctactivation for Pb-208 which was entered as barns rather than mbarns
 * Use Aug 2023 update to CXRO scattering factors (Pt, Cr, Nb, Y, Er)
+* Update physical constants to CODATA 2022. Relative change up to 1e-7 in
+  Avogadro number, Planck constant, J/eV, electron radius, electron mass,
+  neutron mass and atomic mass constant. `planck_constant` is now in J/Hz rather
+  than eV s.
 
 2024-07-08 R1.7.1
 -----------------

periodictable/constants.py

@@ -4,28 +4,30 @@
 Various fundamental constants.
 """
 
-#: Avogadro's number (mol^-1)
-avogadro_number = 6.02214179e23 #(30) mol^-1
-#: Planck's constant (eV s)
-plancks_constant = 4.13566733e-15 #(10) eV s
-#: Electron volt (J/eV)
-electron_volt = 1.602176487e-19 #(40) J / eV
-#: speed of light c (m/s)
-speed_of_light = 299792458 # m/s (exact)
-#: electron radius r_e (m)
-electron_radius = 2.8179402894e-15 #(58) m
+#: Avogadro's number (mol^-1) [CODATA 2022]
+avogadro_number = 6.02214076e23 #(exact) 1/mol [CODATA 2022]
+#: Planck constant (eV s) [CODATA 2022]
+planck_constant = 6.62607015e-34 #(exact) J/Hz [CODATA 2022]
+#: Electron volt (J/eV) [CODATA 2022]
+electron_volt = 1.602176634e-19 #(exact) J / eV [CODATA 2022]
+#planck_constant_eV = planck_constant / electron_volt
+#: speed of light c (m/s) [CODATA 2022]
+speed_of_light = 299792458 #(exact) m/s [CODATA 2022]
+#: electron radius r_e (m) [CODATA 2022]
+electron_radius = 2.8179403205e-15 #(13) m [CODATA 2022]
 
 # [CODATA] From NIST Reference on Constants, Units, and Uncertainty
 #   http://physics.nist.gov/cuu/index.html
 # [AME2020] "The Ame2020 atomic mass evaluation (II)"
 #     by M.Wang, W.J.Huang, F.G.Kondev, G.Audi and S.Naimi
 #     Chinese Physics C45, 030003, March 2021.
-#: neutron mass (u)
-neutron_mass = 1.00866491590 #(47) u [AME 2020]
-neutron_mass_unc = 0.00000000047
-#neutron_mass = 1.00866491597 #(43) u [CODATA 2010?]
-#neutron_mass = 1.00866491595 #(49) u [CODATA 2018]
-#: atomic mass constant (kg / u)
-atomic_mass_constant = 1.660538782e-27 #(83) kg / u
-#: electron mass (u)
-electron_mass = 5.48577990946e-4 #(22) u
+#: neutron mass (u) [CODATA 2022]
+neutron_mass     = 1.00866491606 #(40) u [CODATA 2022]
+neutron_mass_unc = 0.00000000040
+#neutron_mass    = 1.00866491590 #(47) u [AME 2020]
+#neutron_mass    = 1.00866491597 #(43) u [CODATA 2006]
+#neutron_mass    = 1.00866491595 #(49) u [CODATA 2018]
+#: atomic mass constant (kg / u) [CODATA 2022]
+atomic_mass_constant = 1.66053906892e-27 #(52) kg / u [CODATA 2022]
+#: electron mass (u) [CODATA 2022]
+electron_mass = 5.485799090441e-4 #(97) u [CODATA 2022]

periodictable/nsf.py

@@ -157,7 +157,7 @@
 import numpy as np
 from numpy import sqrt, pi, asarray, inf
 from .core import Element, Isotope, default_table
-from .constants import (avogadro_number, plancks_constant, electron_volt,
+from .constants import (avogadro_number, planck_constant, electron_volt,
                         neutron_mass, atomic_mass_constant)
 from .util import require_keywords, parse_uncertainty
 
@@ -173,24 +173,24 @@
            #'scattering_potential',
           ]
 
-ABSORPTION_WAVELENGTH = 1.798
+#: Wavelength [Å] for which neutron scattering cross sections are tabulated.
+ABSORPTION_WAVELENGTH = 1.798 # [Å]
 
 
-# Velocity (m/s) <=> wavelength (A)
-#   lambda = h / p = h (eV) (J/eV) / ( m_n (kg) v (m/s) ) (10^10 A/m)
-#
-# Since plancks constant is in eV
-#   lambda = (1e10 * h*electron_volt/(neutron_mass/N_A)) / velocity
-
-# Energy (eV) <=> wavelength (A)
-#   h^2/(2 m_n kg lambda A) (10^20 A/m) (1000 meV/eV) / (electron_volt J/eV)
-# Since plancks constant is in eV
-#   (h J)^2/electron_volt = ((h eV)(electron_volt J/eV))^2/electron_volt
-#                         = (h eV)^2 * electron_volt
-ENERGY_FACTOR = (plancks_constant**2*electron_volt
-                 / (2 * neutron_mass * atomic_mass_constant)) * 1e23
-VELOCITY_FACTOR = (plancks_constant*electron_volt
-                   / (neutron_mass * atomic_mass_constant)) * 1e10
+#: Energy [eV] <=> wavelength [Å]:
+#:   E = 1/2 m v² = h² / (2 m λ²)
+#:   E[meV s]  = h[J s]²/(2 m_n[u] m_u[kg/u] λ[Å]²/10^20[Å/m])
+#:             * 1000[meV/eV] / electron_volt[J/eV]
+ENERGY_FACTOR = (
+    1e23 * planck_constant**2/electron_volt
+    / (2 * neutron_mass * atomic_mass_constant))
+
+#: Velocity[m/s] <=> wavelength[Å]:
+#:  h = p λ = m v λ
+#:  λ[Å] = h[J s] / ( m_n[kg] v[m/s] ) 10^10[Å/m]
+VELOCITY_FACTOR = (
+    1e10 * planck_constant / (neutron_mass * atomic_mass_constant))
+
 def neutron_wavelength(energy):
     r"""
     Convert neutron energy to wavelength.
@@ -210,7 +210,7 @@ def neutron_wavelength(energy):
 
     where
 
-        $h$ = planck's constant in |Js|
+        $h$ = Planck constant in |Js|
 
         $m_n$ = neutron mass in kg
 
@@ -235,7 +235,7 @@ def neutron_wavelength_from_velocity(velocity):
 
     where
 
-        $h$ = planck's constant in |Js|
+        $h$ = Planck constant in |Js|
 
         $m_n$ = neutron mass in kg
     """
@@ -259,7 +259,7 @@ def neutron_energy(wavelength):
 
     where:
 
-        $h$ = planck's constant in |Js|
+        $h$ = Planck constant in |Js|
 
         $m_n$ = neutron mass in kg
     """
@@ -289,7 +289,7 @@ def _CHECK_scattering_potential(sld):
 
         $\hbar = h / (2 \pi)$
 
-        $h$ = planck's constant in |Js|
+        $h$ = Planck constant in |Js|
 
         $N_b = \sum{ n_i b_i } / V$
 

periodictable/xsf.py

@@ -192,8 +192,9 @@
 from numpy import nan, pi, exp, sin, cos, sqrt, radians
 
 from .core import Element, Ion, default_table, get_data_path
-from .constants import (avogadro_number, plancks_constant, speed_of_light,
-                        electron_radius)
+from .constants import (
+    avogadro_number, planck_constant, speed_of_light, electron_volt,
+    electron_radius)
 from .util import require_keywords
 
 def xray_wavelength(energy):
@@ -214,11 +215,11 @@ def xray_wavelength(energy):
 
     where:
 
-        $h$ = planck's constant in eV\ |cdot|\ s
+        $h$ = Planck constant in J\ |cdot|\ s
 
         $c$ = speed of light in m/s
     """
-    return plancks_constant*speed_of_light/numpy.asarray(energy)*1e7
+    return planck_constant/electron_volt*speed_of_light/numpy.asarray(energy)*1e7
 
 def xray_energy(wavelength):
     r"""
@@ -238,11 +239,11 @@ def xray_energy(wavelength):
 
     where:
 
-        $h$ = planck's constant in eV\ |cdot|\ s
+        $h$ = Planck constant in J\ |cdot|\ s
 
         $c$ = speed of light in m/s
     """
-    return plancks_constant*speed_of_light/numpy.asarray(wavelength)*1e7
+    return planck_constant/electron_volt*speed_of_light/numpy.asarray(wavelength)*1e7
 
 class Xray(object):
     """

test/test_density.py

@@ -7,8 +7,8 @@ def test():
     assert elements.D.density == elements.H.density * elements.D.mass/elements.H.mass
 
     # check number density and unit cell width
-    assert abs(elements.Ca.interatomic_distance - 3.50166387163) < 1e-10
-    assert abs(elements.Fe.number_density - 8.4910635606518029e+22) < 1e12
+    assert abs(elements.Ca.interatomic_distance - 3.5016640712645786) < 1e-10
+    assert abs(elements.Fe.number_density - 8.491062108378546e+22) < 1e12
     assert elements.Ca.interatomic_distance_units == "angstrom"
     assert elements.Fe.number_density_units == "1/cm^3"
 

test/test_nsf.py

@@ -123,8 +123,8 @@ def test():
     assert abs(depth-depth2)<1e-14
 
     # Test energy <=> velocity <=> wavelength
-    # PAK: value changes with updated neutron and atomic mass constants [2023-08]
-    assert abs(nsf.neutron_wavelength_from_velocity(2200) - 1.7981972619684314) < 1e-14
+    # PAK: value changes with updated neutron and atomic mass constants [2024-10]
+    assert abs(nsf.neutron_wavelength_from_velocity(2200) - 1.7981972755018132) < 1e-14
     assert abs(nsf.neutron_wavelength(25) - 1.8) < 0.1
     assert abs(nsf.neutron_energy(nsf.neutron_wavelength(25)) - 25) < 1e-14