PURE FUNCTION H2_cool(nH2, nH, T)

Defined in

contrib/astro/physics/cool/cool.f90

Inputs:

• nH2 (cm^-3)
• nH (cm^-3)
• T (K)

Description

• Computes the energy source term from H2 radiative cooling due to collisional de-excitation from H-H2 & H2-H2 collisions)
• Values are in ergs/cm³/s
• Based on cooling rate coefficients (ergs/s) from Lepp & Schull (1983ApJ…270…578L), along with their cooling rate function (ergs/cm³/s)

Specifics

• Cooling = 0 if nH2 is small (<10^-6)
• Only valid for T ⇐ 10⁶K (if T > 10⁶, it is set to 10⁶K)
• The vibrational and rotational coefficients due to collisions are defined in the functions listed below.
  • The high density limit (for Lvh, Lrh) is n < 1 cm^-3
  • The low density limit (for Lvl, Lrl) is n > 10⁶ cm^-3
• The H2 cooling is calculated using the vibrational and rotational coefficients according to the cooling rate function, but then subtracting off the H2 heating.
• The H2 heating is calculated using the same function as the cooling, but without nH2 as a factor, and using MinTemp (defined in physics.data) as the temperature. I'm not sure where this came from.

Contains

PURE FUNCTION Lvh(T)

• PURE FUNCTION Lvh
  • Sets Vibrational cooling coefficient for high densities
  • in ergs/s
  • Lvh = 1.10d-18 * exp(-6744./T)

PURE FUNCTION Lvl(T)

• PURE FUNCTION Lvl
  • Sets Vibrational cooling coefficient for low densities
  • in ergs/s
  • Lvl = 8.18d-13 * (nH*kH(T) + nH2*FUNCTION kh2(T) kH2(T))

• PURE FUNCTION Lrh
  • Sets Rotational cooling coefficient for high densities
• PURE FUNCTION Lrl
  • Sets Rotational cooling coefficient for low densities
• PURE FUNCTION Qfunc
  • Bridges gap between high and low densities for rotational coefficients

PURE FUNCTION kh2(T)

• PURE FUNCTION kh2
  • Sets rate coefficient for H2-H2 collisions; used to calculate Lvl
• PURE FUNCTION kh
  • Sets rate coefficient for H-H2 collisions; used to calculate Lvl

Called in

contrib/astro/physics/cool/i_evolove.f90