Loading [MathJax]/jax/output/HTML-CSS/jax.js
Skip to main content
Library homepage
 

Text Color

Text Size

 

Margin Size

 

Font Type

Enable Dyslexic Font
Chemistry LibreTexts

Physical Constants

( \newcommand{\kernel}{\mathrm{null}\,}\)

Physical Constants Unit
Atomic mass unit (u) 1 u = 1.66053906660 × 10−24 g
1 g = 6.0221407621 × 1023 u
Avogadro’s number (NA) 6.022142 × 1023/mol
Boltzmann’s constant (k) 1.380651 × 10−23 J/K
Charge on electron (e) 1.60217634 × 10−19 C
Faraday’s constant (F) 9.6485338 × 104 C/mol
Gas constant (R) R=k NA

0.0820575 (L atm)/(mol K)

= 8.31447 J/(mol K)

Mass of electron (mn) 5.485799 × 10−4 amu
= 9.109383 × 10−28 g
Mass of neutron (mn) 1.0086649 u
= 1.6749273 × 10−24 g
Mass of proton (mp) 1.0072765 u
= 1.6726217 × 10−24 g
Pi π = 3.1415927
Planck’s constant (h)

h = 6.626069 × 10 34J s

=h2π=1.05457266·10-34 J·s

Speed of light in vacuum (c) c = 2.99792458 × 108 m/s (exact)
Permeability of vacuum μ0

μ0=4π ·10-7 T2·m3/J

12.566370614·10-7 T2·m3/J

Permittivity of vacuum ϵ0

ϵ0=1μoc2

8.854187817·10-12 C2/J·m

Fine structure constant α 1137.0359895
Bohr magneton μB

μB=eh4πme

9.2740154·10-24 J/T

Nuclear magneton μN

μN=eh4πmp

5.0507866·10-27 J/T

Free electron g factor ge

2.002319304386

Free electron gyromagnetic ratio γe

γe=2geBh

1.7608592·1011 1/s·T

γe2π = 28.024944 GHz/T

Electron magnetic moment μe

μe=geμB2

-9.2847701·10-24 J/T

Proton gyromagnetic ratio (H2O) γp

2.67515255·108 1/s·T

γp2π = 42.576375 MHz/T

Proton magnetic momentμp

1.41060761·10-26 J/T

Charge-to-mass ratio for the electron eme

1.75880·1011 C/kg

Bohr radius a0

5.29177·10-11 m

Electron radius re

2.81792·10-15 m

Proton g factor (Landé factor) gH 5.585
Gravitational constant G

(6.673 ± 0.010)·10-11 m3/kg·s2 (CODATA)

Acceleration due to gravity g

9.80665 m/s2

Compton wavelength of the electron λc 2.42631·10-12 m
Atomic energy unit Hartree

1 Hartree = e24πϵoa0

1 Hartree = 2.625501·106 J/mol (approx. 627.5 kcal/mol)

Proton Larmor frequency

νp=γp/2πB

νp = 42.5764 MHz/T (H2O)

Electron Larmor frequency

νe = νe2π (g / ge) B

νe [GHz] = 13.9962 g B [T]

g = 0.07144775 νe [GHz] / B [T]

g = 3.04199νe [GHz] / νp [MHz]

B [T] = 0.0234872 νp [MHz]

Conversion of Units

1 G = 0.1 mT

1 T = 10 kG

1 mT = 10 G

A [MHz] = 2.80249 (g / ge) A [G]

A [MHz] = 28.0249 (g / ge) A [mT]

A [MHz] = 13.9962 g A [mT]

A [MHz] = 2.99792·104 A [cm-1]

A [cm-1] = 0.333564·10-4 A [MHz]

A [cm-1] = 4.66863·10-4 g A [mT]

 

(Note that the use of brackets [ ] in the following expressions is not in accordance with standards which require the use of a slash, e.g. A/MHz.)

Template:HideTOC

 

Physical Constants is shared under a CC BY-NC-SA 4.0 license and was authored, remixed, and/or curated by LibreTexts.

Support Center

How can we help?