CASSI interaction

The method has become known as the CASSCF State Interaction (CASSI) method and is also effective for long CAS-CI expansions and was recently extended to handle the integrals of the spin-orbit Flamiltonian.34... 

There exists today an alternative approach which has made MCSCF calculations on excited states feasible, also for rather large systems. A method has been developed which makes it easy to obtain orthogonal wave functions and transition densities from CASSCF wave functions optimized independently for a number of excited states of different or the same symmetry as the ground state. The method has been called the CAS State Interaction (CASSI) method. It will be briefly described below. 

These results and also the results for the excitation energies will of course be modified by dynamical correlation effects, which will be accounted for by means of MR-CI calculations based on the CASSCF orbitals for each state. The transition moments will be computed using the CASSI method, where the two A are allowed to interact. The final results can be expected to be accurate to within 0.1 eV for the excitation energies and 10% for the transition moments. The study of the CCCN system is not yet finished. Hopefully some result can be presented in the lectures. 

CASSCF wave functions with their own sets of optimized orbitals, which where then not orthogonal to each other. The CAS State interaction CASSI, method made it possible to compute efficiently first and second order transition density matrices for any type of CASSCF wave functions [16, 17]. The method is used to compute transition dipole moments in spectroscopy and also in applications where it is advantageous to use localized orbitals, for example in studies of charge transfer reactions [18]. Today, the same approach is used to construct and solve a spin-orbit Hamiltonian in a basis of CASSCF wave functions [19]. 

A method to deal with this problem was solved by P.-A. Malmqvist 20 years ago [64,65]. The method has become known as the CASSCF State Interaction (CASSI) method and is effective also for long CAS-CI expansions. It was recently extended to deal also with the integrals of the spin-orbit Hamiltonian [66]. The whole approach has been implemented in the latest version of the MOLCAS quantum chemistry software [67]. 

The second theory, the Cassie-Baxter theory [75], describes a superhydrophobic surface with contact angle, independently of the value of roughness. A surface is described as a composite material (material + air) and the water droplet interacts either with the material or the trapped air. Therefore, the contact angle relation is as follows ... 

The surface roughness, r, is defined as the ratio of the actual surface area to the horizontal projection of the surface area. In the Cassie-Baxter model, the interaction of the fluid with the air trapped in the gaps of rough (or porous) surfaces is considered alongside the liquid-solid interaction. The effect is strongest in the case of water, which forms a contact angle of 180° with air. The Cassie-Baxter model introduces a surface fraction parameter, /, which represents... 

Heart-Lung Interactions in Health and Disease, edited by S.M.ScharfandS.S.Cassi< ... 

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