Coupled cluster response

Spin-Orbit Coupling Constants from Coupled-Cluster Response Theory. 

Dunning s correlation consistent basis sets cc-pVAZ [27] augmented with diffuse functions [28] were used in the calculations. We considered cardinal numbers X—D, T, Q, 5, 6 and single (s), double (d), triple (t), and quadruple (q) augmentations. The orbitals were not allowed to relax in the coupled cluster response calculations. 

Neiss, C., Hattig, C. Frequency-dependent nonlinear optical properties with explicitly correlated coupled-cluster response theory using the CCSD(R12) model. J. Chem. Phys. 2007, 126, 154101. 

O. Christiansen and K. V. Mikkelsen, Coupled cluster response theory for solvated molecules in equilibrium and nonequilibrium solvation, J. Chem. Phys., 110 (1999) 8348. 

Koch H, Jprgensen P (1990) Coupled cluster response functions. J Chem Phys 93 3333—3344. 

In the present paper, we show that it is possible to calculate both vibrational and electronic transitions of H2SO4 with an accuracy that is useful in atmospheric simulations. We calculate the absorption cross sections from the infrared to the vacuum UV region. In Section 2 we describe the vibrational local mode model used to calculate OH-stretching and SOH-bending vibrational transitions as well as their combinations and overtones [42-44]. This model provides frequencies and intensities of the dominant vibrational transitions from the infrared to the visible region. In Section 3 we present vertical excitation energies and oscillator strengths of the electronic transitions calculated with coupled cluster response theory. These coupled cluster calculations provide us with an accurate estimate of the lowest... 

H. Koch and P. Jorgensen, /. Chem. Phys., 93, 3333 (1990). Coupled Cluster Response Functions. 

In the next section we summarize the theoretical background for coupled cluster response theory and discuss certain issues related to their actual implementation. In Sections 3 and 4 we describe the application of quadratic and cubic response in calculations of first and second hyperpolarizabilities. The use of response theory to calculate magneto-optical properties as e.g. the Faraday effect, magnetic circular dichroism, Buckingham effect, Cotton-Mouton effect or Jones birefringence is discussed in Section 5. Finally we give some conclusions and an outlook in Section 6. 

Coupled cluster response calculaAons are usually based on the HF-SCF wave-function of the unperturbed system as reference state, i.e. they correspond to so-called orbital-unrelaxed derivatives. In the static limit this becomes equivalent to finite field calculations where Aie perturbation is added to the Hamiltonian after the HF-SCF step, while in the orbital-relaxed approach the perturbation is included already in the HF-SCF calculation. For frequency-dependent properties the orbital-relaxed approach leads to artificial poles in the correlated results whenever one of the involved frequencies becomes equal to an HF-SCF excitation energy. However, in Aie static limit both unrelaxed and relaxed coupled cluster calculations can be used and for boAi approaches the hierarchy CCS (HF-SCF), CC2, CCSD, CC3,... converges in the limit of a complete cluster expansion to the Full CI result. Thus, the question arises, whether for second hyperpolarizabilities one... 

Verdet constants have been investigated in [74] and [38] for a few centro-symmetric molecules using coupled-cluster response-theory techniques. For atoms, corresponding results can be found in [149]. 

Christiansen et al. s tested the coupled-cluster response theory on spin-orbit coupling constants of substituted silylenes (HSiX, X = F, Cl, Br) in the atomic mean-field approximation. Comparison with the full Breit-Pauli showed that the approximation is quite accurate. The calcu-... 

Coupled cluster response theory, 27 Coupled cluster single-double (CCSD), 10 C-PCM method, viii... 

Abstract In this review we discuss the theory and application of methods of excited state quantum chemistry to excited states of transition metal complexes. We review important works in the field and, in more detail, discuss our own studies of electronic spectroscopy and reactive photochemistry. These include binary metal carbonyl photodissociation and subsequent non-adiabatic relaxation, Jahn-Teller and pseudo-Jahn-Teller effects, photoisomerization of transition metal complexes, and coupled cluster response theory for electronic spectroscopy. We aim to give the general reader an idea of what is possible from modem state-of-the-art computational techniques applied to transition metal systems. 

For relatively small molecules, multiphoton transition moments are in principle available with high accuracy resorting to a coupled-cluster response theory approach... 

Coupled cluster response functions were derived by Koch and Jprgensen (1990) starting from a time-dependent version of the transition expectation value Eq. (9.95) of Arponen (1983)... 

In coupled cluster response theory the poles of the hnear response function and thus the vertical excitation energies are then found as eigenvalues of the coupled cluster Jacobian... 

The same problem with the pole structure appears also for coupled cluster response functions, if one defines them as derivatives of a time-average quasi-energy Lagrangian including orbital relaxation, ft is therefore preferable also in the analytical derivative approach like in Section 11.4 to derive coupled cluster response functions as derivatives of a time-dependent quasi-energy Lagrangian without orbital relaxation... 

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