Specific heatsΒΆ
Please provide the line lists, temperature step Ntemp and the
maximum of the temperature Tmax.
Ntemp is always set as 1 K.
Tmax can be set by yourself and the definition file .def from
the ExoMol database provides the maximum temperature of each molecule
for reference.
The temperatures are start from 1 K to Tmax K in the output file.
The specific heats equation is:
\[
C_p(T) = R\left [\frac{Q''}{Q}-\left (\frac{Q'}{Q} \right )^2 \right ]+\frac{5R}{2},
\]
where the partition function :math:Q(T) and its first two moments are:
\[
Q(T)=\sum_n g_n^{\textrm{tot}}e^{-c_2\tilde{E}_n/T},
\]
\[
Q'(T) = T\frac{\mathrm{d} Q}{\mathrm{d} T} =\sum_n
g_n^{\textrm{tot}}\left(\frac{c_2 \tilde{E}_n}{T}\right)\exp\left(-\frac{c_2 \tilde{E}_n}{T}\right),
\]
\[
Q''(T) = T^2\frac{\mathrm{d}^2 Q}{\mathrm{d} T^2}+2Q' =\sum_n g_n^{\textrm{tot}}
\left(\frac{c_2 \tilde{E}_n}{T}\right)^2\exp\left(\frac{c_2 \tilde{E}_n}{T}\right).
\]
Example: ExoMol
# Data source #
Database ExoMol
Molecule CO2
Isotopologue 12C-16O2
Dataset UCL-4000
SpeciesID 21
# File path #
ReadPath /mnt/data/exomol/exomol3_data/
SavePath /home/jingxin/data/pyexocross/
LogFilePath /home/jingxin/data/pyexocross/log/CO2_ExoMol_cp.log
# Functions #
Conversion 0
PartitionFunctions 0
SpecificHeats 1
CoolingFunctions 0
Lifetimes 0
OscillatorStrengths 0
StickSpectra 0
CrossSections 0
# Cores and chunks #
NCPUtrans 1
NCPUfiles 1
ChunkSize 1000000
# Calculate partition, specific heats or cooling functions #
Ntemp 1 # The number of temperature steps
Tmax 5000 # Maximal temperature in K
Example: HITRAN
# Data source #
Database HITRAN
Molecule NO
Isotopologue 14N-16O
Dataset NO-HITRAN
SpeciesID 81
# File path #
ReadPath /home/jingxin/data/HITRAN/
SavePath /home/jingxin/data/pyexocross/
LogFilePath /home/jingxin/data/pyexocross/log/NO_HITRAN_cp.log
# Functions #
Conversion 0
PartitionFunctions 0
SpecificHeats 1
CoolingFunctions 0
Lifetimes 0
OscillatorStrengths 0
StickSpectra 0
CrossSections 0
# Cores and chunks #
NCPUtrans 1
NCPUfiles 1
ChunkSize 1000000
# Calculate partition, specific heats or cooling functions #
Ntemp 1 # The number of temperature steps
Tmax 5000 # Maximal temperature in K