Getting started with pyglenn

This notebook walks through the essential workflow of the pyglenn library:

Connect to the thermochemical database (bundled, no manual setup);
Look up a chemical species;
Compute \(C_p(T)\), \(H^\circ(T)\) and \(S^\circ(T)\) at a given temperature.

The thermo.db database ships inside the package — just instantiate ThermochemicalCalculator with no arguments.

from pyglenn import ThermochemicalCalculator

print('pyglenn imported successfully')

pyglenn imported successfully

Looking up a species

Use get_available_species with a search pattern to find the identifier (id) of the species you want.

with ThermochemicalCalculator() as calc:
    species = calc.get_available_species('CH4')

for s in species[:5]:
    print(f"id={s['id']:>5}  {s['name']:<12}  phase={s['phase']}")

id=  296  CH4           phase=gas

Computing thermochemical properties

With the id in hand, calculate_properties(species_id, temperature) returns a dictionary with \(C_p\), \(H^\circ\) (relative to 0 K) and \(S^\circ\).

with ThermochemicalCalculator() as calc:
    species_id = calc.get_available_species('CH4')[0]['id']
    result = calc.calculate_properties(species_id, 298.15)

print(f"Species : {result['species_name']} ({result['phase']})")
print(f"T       : {result['temperature']:.2f} K")
print(f"Cp      : {result['cp']:.3f} J/(mol·K)")
print(f"H°      : {result['h_relative']:.3f} J/mol")
print(f"S°      : {result['s']:.3f} J/(mol·K)")

Species : CH4 (gas)
T       : 298.15 K
Cp      : 35.691 J/(mol·K)
H°      : -74599.575 J/mol
S°      : 186.370 J/(mol·K)

Sweeping a temperature range

A common task is to evaluate \(C_p\) across several temperatures.

temperatures = [300.0, 500.0, 800.0, 1000.0, 1500.0]

with ThermochemicalCalculator() as calc:
    species_id = calc.get_available_species('CH4')[0]['id']
    print(f"{'T (K)':>8} | {'Cp (J/mol·K)':>14}")
    print('-' * 27)
    for T in temperatures:
        r = calc.calculate_properties(species_id, T)
        print(f"{T:>8.1f} | {r['cp']:>14.3f}")

   T (K) |   Cp (J/mol·K)
---------------------------
0 |         35.760
0 |         46.584
0 |         64.012
0 |         73.676
0 |         90.865