Applying a Smolyak collocation method to Cl₂CO

ABSTRACT

Phosgene (Cl₂C=O) is extremely poisonous, underscoring the importance of accurate infrared detection. Here, the computed vibrational energy levels of phosgene are reported for the first time from a six-dimensional potential energy surface (PES) that was constructed from 25,000 single-point energy computations at the CCSD(T)/cc-pVTZ level of theory. The computed points were fit using a neural network method, and the resulting PES was employed in the determination of vibrational energies and wavefunctions. Bond coordinates were utilised in conjunction with a collocation method to minimise problems that arise from the complicated nature of the kinetic energy operator. The collocation method makes possible the computation of energy levels without integral evaluation, and without the need to solve a generalised eigenvalue problem. Moreover, it is built on a nondirect product-pruned basis that is much smaller than the direct product basis that would be required to obtain the same accuracy.

KEYWORDS:

• Vibrational spectroscopy
• collocation
• phosgene
• neural networks

Acknowledgments

Tucker Carrington thanks André D. Bandrauk for his infectious and inspiring love of science.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This work was supported by the Natural Sciences and Engineering Research Council of Canada. Computations were performed on resources purchased with funds from the Canada Foundation for Innovation. Sergei Manzhos was supported by the Ministry of Education of Singapore. Work performed at the University of Georgia was supported by the National Science Foundation [grant number CHE-1361178].