Applying a Smolyak collocation method to Cl2CO. (18th August 2017)

• Record Type: Journal Article
• Authors: Castro, Eduardo; Avila, Gustavo; Manzhos, Sergei; Agarwal, Jay; Schaefer, Henry F.; Carrington, Tucker
• Is Part Of: Molecular physics. Volume 115:Number 15/16(2017)
• Page Start: 1775
• Page End: 1785
• Publication Date: 2017-08-18
• Subjects: Vibrational spectroscopy -- collocation -- phosgene -- neural networks; Molecules -- Periodicals; Chemistry, Physical and theoretical -- Periodicals; Molécules -- Périodiques; Chimie physique et théorique -- Périodiques; 539.6.05
• DOI: 10.1080/00268976.2016.1271153
• Languages: English
• ISSNs: 0026-8976

Abstract

ABSTRACT: Phosgene (Cl2 C=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. Abstract :