Conversion Factors

Energy Conversion Factors

1 kcal/mol
0.04336 eV
0.00159 h
349.75 cm$^{-1}$
6.948 × 10$^{-14}$ erg
4.184 kJ/mol
1 eV
23.06 kcal/mol
0.03675 h
8065.6 cm$^{-1}$
1.602 × 10$^{-12}$ erg
1 h
627.51 kcal/mol
27.212 eV
219,474.6 cm$^{-1}$
4.36 × 10$^{-11}$ erg
2 Ry
1 erg
1.439 × 10$^{13}$ kcal/mol
6.2415 × 10$^{11}$ eV
2.2937 × 10$^{10}$ h
5.034 × 10$^{15}$ cm$^{-1}$

Colors of Light

Visible Light

Color nm eV $\text{cm}^{-1}$
Red 700 1.77 14,300
Orange 620 2.00 16,100
Yellow 580 2.14 17,300
Green 530 2.34 18,900
Blue 470 2.64 21,300
Violet 420 2.95 23,800

All Light

Color nm eV $\text{cm}^{-1}$
Radio $3\times 10^{12}$ — $3\times 10^{8}$ $4\times 10^{-10}$ — $4\times 10^{-6}$ $3\times 10^{-6}$ — $3\times 10^{-2}$
Microwaves $3\times 10^{8}$ — $3\times 10^{6}$ $4\times 10^{-6}$ — $4\times 10^{-4}$ $3\times 10^{-2}$ — $3$
Far IR $3\times 10^{6}$ — $3\times 10^{4}$ $4\times 10^{-4}$ — $4\times 10^{-2}$ $3$ — $300$
Near IR $3\times 10^{4}$ — $700$ $4\times 10^{-2}$ — $2$ $300$ — $15,000$
Visible $700$ — $420$ $2$ — $3$ $15,000$ — $24,000$
Near UV $420$ — $300$ $3$ — $4$ $24,000$ — $30,000$
Vac UV $300$ — $3$ $4$ — $400$ $30,000$ — 3\e{6}
X-rays $3$ — $0.003$ $400$ — $4\times 10^{5}$ $3\times 10^{6}$ — $3\times 10^{9}$

Free Energies

$$ \Delta(G) = RT \ln(K) $$ $$ \Delta(G_1) - \Delta(G_2) = RT\ln\left(\frac{K_1}{K_2}\right) $$ $$ \Delta\Delta(G) = 1\text{ kcal/mol} \Longleftrightarrow \frac{K_1}{K_2} = 5.4 $$ $$ \frac{K_1}{K_2} = 10^1 \Longleftrightarrow \Delta\Delta G = 1.36 $$ $$ \frac{K_1}{K_2} = 10^2 \Longleftrightarrow \Delta\Delta G = 2.76 $$ $$ \frac{K_1}{K_2} = 10^4 \Longleftrightarrow \Delta\Delta G = 5.53 $$ $$ \frac{K_1}{K_2} = 10^6 \Longleftrightarrow \Delta\Delta G = 8.29 $$ $$ \Delta G = 1.36 \left( pK_{a1} - pK_{a2}\right) $$

Atomic Units

Length Bohr radius, $a_0$ 0.52918 Å
Force Constant 1 au $1.5569 \times 10^6$ dyn/cm
Mass au, m$_\text{e}$ $9.1095\times 10^{-31}$ kg
$5.5\times 10^{-4}$ amu
amu, m($^{12}$C)/12 $1.66\times 10^{-27}$ kg
1822 au
Time au $2.4189\times 10^{-17}$ s
Dipole Moment au 2.54 D
$8.478\times 10^{-30}$ C-m

Miscellaneous

Force Constants

$$ 1\text{ dyn/cm} = 1.44 \times 10^{-3}\frac{\text{ kcal/mol}}{\text{Å}^2} $$ $$ 1\text{ Mdyn/cm} = 1440\frac{\text{ kcal/mol}}{\text{Å}^2} $$

Thermal

$$ k_BT (298\text{ K}) = 9.4366 \times 10^{-4}\text{ h} $$ $$ RT (298\text{ K}) = 2.4789\text{ kJ/mol} = 0.5925\text{ kcal/mol} $$ $$ e^2 = 14.3998\text{ eV-Å} = 332.059\text{ (kcal/mol)-Å} $$

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David P. Hoffman
Staff Optical Engineer @ 10x Genomics

I’m a scientist/engineer who builds robust, high-performance optical systems and loves data and python. Views are my own (whose else’s would they be?)

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