\chapter{CONVERSION FACTORS}
% !TEX root = hazy2.tex

Table \ref{tab:ConversionFactors} gives conversion factors between
various common units.
The last column of the table gives the variable names for
constants that occur within the code.
Most are defined as macros within the header file
\cdCommand{physconst.h}.
These should be used instead of entering the constant directly.
In the following all Rydbergs are for infinite mass nuclei.

The fundamental constants used by the code are from the
\href{http://physics.nist.gov/cuu/Constants/index.html}{CODATA
recommended values}
and are in the header file \cdFilename{physconst.h}.
Derived quantities should be
formed from the fundamental quantities given there, so that any future
changes will trickle down into all parts of the code.

\begin{table}\caption{Conversion Factors}
\label{tab:ConversionFactors}
{\small
\begin{tabular}{lllll}
\hline
To convert from& Variable& to& multiply by& Parameter\\
\hline
AU&&cm& 1.49597870(13)&\\
Boltzmann
constant& BOLTZMANN& 1.3806503(-16)\\
cm&& micron($\mu$m)& $10^4$\\
phot/s/cm$^2$& flux& f$_\nu$& $\nu_{\mathrm{Ryd}}$h$\nu_1$ (erg)\\
phot/Ryd/s/cm$^2$& flux/widflx& $\nu f_\nu$& $\nu_{\mathrm{Ryd}}^2$ h$\nu_1$
(erg)\\
phot/Ryd/s/cm$^2$& flux/widflx& J$_\nu$& $\nu_{\mathrm{Ryd}}$ h\\
optical depth& tautot& A$_{\mathrm{V}}$(mag)& 1.08574\\
energy
(eV)&&  ergs& 1.602192($-$12)\\
energy (eV)&& K& 1.1604448(4)&\cdVariable{ eVdegK}\\
energy (keV)&& Frequency
Hz& 2.41799($+$17)\\
energy (Ryd)& anu& Kelvin& 1.5788866(5)& \cdVariable{Te1ryd}\\
energy
(Ryd)&anu& ergs& 2.179874($-$11)& \cdVariable{en1ryd}\\
energy (Ryd)& anu& cm$^{-1}$& 109737.315& \cdVariable{1/WavNRyd}\\
energy
(Ryd)& anu& eV& 13.6056981& \cdVariable{evRyd}\\
energy (Ryd)& anu& \AA& 911.6/energy(Ryd) & \cdVariable{rydlam}\\
energy (Ryd), T& anu,
Te& h$\nu$/kT& 1.5788866(5)*anu/Te& \cdVariable{Te1ryd}\\
temperature (K)& Te& eV& 8.617385($-$5)\\
temperature
(K)& Te& ergs& 1.38063($-$16)& \cdVariable{boltzmann}\\
temperature (K)& Te& Rydbergs& 1/1.5788866(5)&
\cdVariable{1/te1ryd}\\
wavelength (\AA )&& meters& 1(-10)\\
wavelength (\AA )&& ergs& 1.9864(-8)/$\lambda$(\AA)\\
wavelength (\AA )&& degree K& 1.43877($+$8)/$\lambda$(\AA )\\
wavelength
(cm)& micron& 1($+$4)\\
wavelength (cm)& \AA& 1($+$8)\\
wavelength
(cm)&& ergs& 1.9864($-$12)/$\lambda$(cm)\\
wavelength (cm)&& degree K& 1.43877/$\lambda$(cm)\\
wavelength
(cm)&& Rydbergs& 9.11256($-$6)/$\lambda$(cm)\\
wavelength (micron)&& degree
K& 1.43877($+$4)/$\lambda(\mu)$\\
wavelength (micron)&& ergs& 1.9864($-$12)/$\lambda(\mu)$\\
wavenumbers (
cm$^{-1}$)&& ergs& 1.98648($-$16)\\
wavenumbers ( cm$^{-1}$)&& degree K& 1.43877& \cdVariable{WavNKelv}\\
wavenumbers
( cm$^{-1}$)&& Rydbergs& 9.1126732($-$6)& \cdVariable{WavNRyd}\\
\hline
\end{tabular}
}\end{table}
