thermochemistry_library 0.0.2

converting Hessian matrices to thermo data

Thermochemistry Library

This library converts a cartesian hessian of nuclear second derivatives into vibrational and thermodynamic quantities, following similar framework used in Gaussian and GoodVibes, but in a modular and Python-native implementation.

Minimum Inputs

• Cartesian Hessian Matrix
• Atomic Masses
• Cartesian Coordinates
• Temperature (K)

Example Outputs

• Vibrational Frequencies
• Normal Modes
• Cartesian Coordinates
• Rotational Constants
• Center of Mass
• Entropy
• Enthalpy
• Gibbs Free Energy

Quasi-Harmonic Corrections

Akin to goodvibes, the Cramer & Truhlar and Grimme (RRHO) approximations were used.

Cramer & Truhlar:
mod_freqs = np.where(mod_freqs < self.qh_cutoff, self.qh_cutoff, mod_freqs)

(qh_cutoff = 100cm^-1)

Grimme:
w = 1.0 / (1.0 + (self.qh_cutoff / valid_freqs)**4)

Credits

This package was created with Cookiecutter and the jevandezande/uv-cookiecutter project template.

This library was in loose collabration with Rowansci