Articles written in Journal of Chemical Sciences
Volume 132 All articles Published: January 2020 Article ID 0003
We propose a perturbative approximation to the vibrational coupled cluster method in bosonic representation to reduce the cost of calculating the cluster matrix elements by considering only the first order of S and r for the construction of the effective Hamiltonian ese-SHeSes. With the systematic analysis of theresults of two molecules, H2O and 1,1-difluoroethylene, we find that the accuracy of the transition energies with such low order approximation is comparable to the fully converged VCCM
Volume 132 All articles Published: January 2020 Article ID 0014
A theory for calculating vibrational energy levels and infrared intensities is developed in the equation of motion framework at the random phase approximation level. The vibrational Hamiltonian is expanded in the harmonic oscillator ladder operators making a Hamiltonian a bosonic Hamiltonian. Theexcitation operator is expanded to include at most two creations and two annihilation operators making it equivalent to the random phase approximation. The method is applied for the calculation of vibrational spectral properties of two molecules. The results are found to be satisfactory, making this approach a viable option for large molecular systems.
Volume 133, 2021
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