Vibration and two-photon absorption

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A variational approach for reliably calculating vibrational linear and nonlinear optical properties of molecules with large electrical and/or mechanical anharmonicity is introduced. This approach utilizes a self-consistent solution of the vibrational Schrödinger equation for the complete field-dependent potential-energy surface and, then, adds higher-level vibrational correlation corrections as desired. An initial application is made to static properties for three molecules of widely varying anharmonicity using the lowest-level vibrational correlation treatment ͑i.e., vibrational Møller-Plesset perturbation theory͒. Our results indicate when the conventional BishopKirtman perturbation method can be expected to break down and when high-level vibrational correlation methods are likely to be required. Future improvements and extensions are discussed.

Section: Theory and Methodological Considerationsmentioning

confidence: 99%

Variational calculation of vibrational linear and nonlinear optical properties

Torrent‐Sucarrat

Luis

Kirtman

2005

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“…[42][43][44] Damped response theory has also been applied in the context of calculating vibrational spectra. [45][46][47] In this paper we use the damped response theory formalism presented in Ref. 8 to calculate two-photon absorption (TPA) spectra.…”

Section: Introductionmentioning

confidence: 99%

Damped response theory description of two-photon absorption

Kristensen

Kauczor

Thorvaldsen

et al. 2011

Damped response theory is applied to the calculation of two-photon absorption (TPA) spectra, which are determined directly, at each frequency, from a modified damped cubic response function. The TPA spectrum may therefore be evaluated for selected frequency ranges, making the damped TPA approach attractive for calculations on large molecules with a high density of states, where the calculation of TPA using standard theory is more problematic. Damped response theory can also be applied to the case of intermediate state resonances, where the standard TPA expression is divergent. Both exact damped response theory and its application within density functional theory are discussed. The latter is implemented using an atomic-orbital based density matrix formulation, which makes the approach especially suitable for studies on large systems. A test preliminary study is presented for the TPA spectrum of R-(+)-1,1 -bi(2-naphtol).

“…In addition, we want to incorporate accurate methods for obtaining the static E ZPVA , such as vibrational CI, [34][35][36] within our procedure. The possibility that an extended FF-NR approach can be adapted for vibrational two photon absorption 37 will also be considered. …”

Section: Summary and Future Outlookmentioning

confidence: 99%

Simple finite field nuclear relaxation method for calculating vibrational contribution to degenerate four-wave mixing

Luis

2008

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A simple extended finite field nuclear relaxation procedure for calculating vibrational contributions to degenerate four-wave mixing ͑also known as the intensity-dependent refractive index͒ is presented. As a by-product one also obtains the static vibrationally averaged linear polarizability, as well as the first and second hyperpolarizability. The methodology is validated by illustrative calculations on the water molecule. Further possible extensions are suggested.