LIST OF SYMBOLS

Ac(r)	Cloud cross section
Aji	Radiative transition rate
a	Damping constant
Bij	Aborption coefficient
bi	Derture coefficient for level i
Cij	Collisional excitation rate
C(r)	Cumulative covering factor (up to distance r)
c	Velocity of light
cs	Sound speed
El(r)	Cumulative line flux (up to distance r)
E	Line profile
E(t)	Emission line light curve
Eij	Energy separation of levels ij
EW	Equivalent width
F	Monochromatic continuum flux
fd	Drag force
fij	Oscillator strength
G	Gravitational constant
gff	Gaunt factor for free-free transition
gG	Gravitational acceleration
gi	Statistical weight of level i
grad	Radiative acceleration
h	Planck's constant
I	Radiation intensity
J	Mean radiation intensity
jc(r)	Total cloud emission
k	Boltzmann constant
k()	Number of scattering factor
k'()	Path length increase factor
L	Integrated continuum luminosity
L46	Luminosity in 1046 erg s-1
L	Monochromatic continuum luminosity
L(t)	Continuum light curve
LEdd	Eddington luminosity
Mc	Mass of a cloud
MBH	Mass of the central black hole
M9	MBH / 109 M
	Accretion rate
	Accretion rate in units of L/LEdd
me	Electron mass
mp	Proton mass
m	Magnitude of extinction
N	Particle number density
N10	N / 1010 cm-3
Ne	Electron density
NHIM	Density of the hot inter-cloud medium
Ncol	Column density
nc(r)	Number of clouds per unit volume at distance r
ni	Population of level i
P	Pressure
Q()	Number of scattering before escape
Rc	Radius of a cloud
r	Distance of a cloud
rav	Emissivity-weighted average radius
rin	Inner radius of the emission line region
rout	Outer radius of the emission line region
S	Source function
TC	Compton temperature
Te	Electron temperature
Tex	Excitation temperature
THIM	Temperature of the hot inter-cloud medium
Trad	Radiation temperature
tdyn	Dynamical time
trec	Recombination time
tsc	Sound-crossing time
U	Ionization parameter
Vc	Volume of a cloud
v(r)	Cloud velocity at a distance r
vDoppler	Doppler velocity
v3000	v/3000 km s-1
Xc	Relative continuum opacity
Xl	Relative line opacity
Z	Nuclear charge
z	Redshift
	Recombination coefficient
T	Temperature averaged recombination coefficient
	Escape probability
eff	Effective escape probability
	Continuum spectral index
l(r)	Line emission (erg s-1 cm-2)
	Line emission coefficient
	Continuum occupation number
	Line absorption coefficient
c	Continuum absorption cross section at line center
l	Line absorption cross section at line center
ij	Wavelength of the ij transition
0	Line center wavelength
µ	cos in a spherical coordinate system
	Frequency
0	Threshold ionization frequency
	Mean photon frequency or mean photon energy
cut	Cut-off frequency
	(radiation pressure) / (gas pressure) U/T
	Continuum absorption cross section
c	Effective Compton cooling cross section
es	Electron scattering cross section
h	Effective Compton heating cross section
	Optical depth
in	Optical depth to the inner (illuminated) face of the cloud
out	Optical depth to the outer face of the cloud
	Normalized line profile
(t)	Transfer function
ij	Effective collision strength
	1 / t