Study of ground and excited states

J.L. Whitten, M. Hackmeyer, Configuration interaction studies of ground and excited states of polyatomic molecules. I. The Cl formulation and studies of formaldehyde, J. Chem. Phys. 51 (1969) 5584. 

Rosa A, Ricciardi G, Baerends EJ, Stufkens DJ (1995) Density-functional study of ground and excited-states of Mn2(CO)io. Inorg Chem 34 3425-3432... 

Flash photolysis studies with absorption or delayed fluorescence detection were performed to compare the binding of ground and excited state guests with DNA.113,136 The triplet lifetimes for 5 and 6 were shown to be lengthened in the presence of DNA.136 The decays were mono-exponential with the exception of the high excitation flux conditions where the triplet-triplet annihilation process, a bimo-lecular reaction, contributed to the decay. The residence time for the excited guest was estimated to be shorter than for the ground state, but no precise values for the rate constants were reported. However, the estimated equilibrium constants for the... 

Analytical gradients and Hessians are available for CASSCF, and it is expected that this technology will be extended to the MR-CI and MP2 methods soon. Further, by virtue of the multireference approach, a balanced description of ground and excited states is achieved. Unfortunately, unlike black boxes such as first-order response methods (e.g., time-dependent DFT), CAS-based methods require considerable skill and experience to use effectively. In the last section of this chapter, we will present some case studies that serve to illustrate the main conceptual issues related to computation of excited state potential surfaces. The reader who is contemplating performing computations is urged to study some of the cited papers to appreciate the practical issues. 

The convenient entry to arylmethyl radicals via homolytic photodissociation of the corresponding halomethylaryl precursors has been used to study the ground and excited state reactivities of -substituted benzyl radicals with 02172,173 and the excited state properties and reactivities of a series of arylmethyl radicals174,175. 

A wide range of ground and excited state atoms and radicals has been produced by laser photolysis. Lin and McDonald [9] have recently reviewed the production of such species by photolysis and they list the many kinetically important atoms and free radicals that can be produced. As the range of available lasers increases, we can expect laser photolysis to become one of the major sources of reactive species for kinetic studies. 

Hydrogen Bond Effects in Fluorescence. The importance of coupling emission studies with absorption spectra has been noted (1633). Together, these spectra permit determination of the zero-zero transition which measures directly the difference between H bond enthalpies of ground and excited states. (For the n —tt transitions, fluorescence data may be difficult to obtain, as noted by Kasha see footnote 11 of 1633.) Of equal interest but more complicated interpretation is the effect of H bond formation on the intensity of fluorescence. Unfortunately, relatively little work has been reported. 

Numerous quantum-chemical ab initio studies include the calculation of ground- and excited-state potential functions tabulated energy values or graphical representations E(r) are given ... 

Steric effect on energetics and dynamics of ground- and excited-state conformations in bis(9-fluorenyl)methane and its derivative 9-(9-ethyl-fluorenyl)-9 -fluorenylmethane has been studied by Boo et The... 

---