Assessment of the Performance of DFT Functionals in the Fulfillment of Off-Diagonal Hypervirial Relationships

2021 ◽  
Author(s):  
Francesco Ferdinando Summa ◽  
Guglielmo Monaco ◽  
Paolo Lazzeretti ◽  
Riccardo Zanasi
Keyword(s):  
Excited State ◽  
State Transition ◽  
Sum Rules ◽  
Quantum Mechanical ◽  
Current Conservation ◽  
Transition Energies ◽  
Electronic Excited State ◽  
Charge Current ◽  
External Reference

Off-diagonal hypervirial relationships, combined with quantum mechanical sum rules of charge-current conservation, offer a way for testing electronic excited-state transition energies and moments, which does not need any external reference....

Calculations on the origin of hyperporphyrin spectra in sequentially protonated meso-(dimethylaminophenyl) porphyrins

2001 ◽  
Vol 05 (03) ◽  
pp. 191-197 ◽  
Author(s):  
MIRNA VITASOVIC ◽  
MARTIN GOUTERMAN ◽  
HENRY LINSCHITZ
Keyword(s):  
Excited State ◽  
Energy Minimization ◽  
Phenyl Ring ◽  
State Transition ◽  
Amino Nitrogen ◽  
Porphyrin Ring ◽  
Transition Energies ◽  
Essentially Normal ◽  
Semi Empirical ◽  
Ci Calculation

The spectra of porphyrins meso-substituted by 4-dimethylaminophenyl groups and protonated at the central pyrrole nitrogens show strong new bands in the visible (450–600 nm) and far-red (700–780 nm). On complete protonation the observed spectra are essentially normal except for enhanced intensity in the farthest red band at ∼ 650 nm. The new bands observed with partial protonation have been qualitatively interpreted as hyperporphyrin spectra due to transitions from 'the filled π orbitals on the amino nitrogen atoms… to the porphyrin LUMOs' [Ojadi ECA, Linschitz M, Gouterman M, Walter RI, Lindsey JS, Wagner RW,]. We now report spectra calculated using the CAChe computer program package. The best structures are determined by energy minimization using a semi-empiral AM1 algorithm; a semi-empirical INDO/CI calculation is then used to obtained the excited state transition energies and intensities. The calculated spectra, although generally blue-shifted compared to experiment, reproduce the hyperporphyrin spectra in those cases where they are observed. In these cases, in contrast to species with normal porphyrin spectra, the HOMO or HOMO-1 is not an orbital on the porphyrin ring but is rather a π-orbital on the unprotonated amino nitrogen that extends over the associated phenyl ring. The calculations suggest that the hyperporphyrin transitions are of Ph (π) → Por (π*) origin, where Ph (π) is an orbital on the phenylamine substitutent and Por (π*) is a LUMO on the porphyrin. It is further suggested that in the fully protonated species the intensity enhancement of the farthest red band in an otherwise normal porphyrin spectrum may relate to phenyl character in the HOMO or HOMO-1.

Renilla Bioluminescence: A Morphologic Approach to the Location of Photocytes

1974 ◽  
Vol 32 ◽  
pp. 208-209
Author(s):  
Ben O. Spurlock ◽  
Milton J. Cormier
Keyword(s):  
Excited State ◽  
Ground State ◽  
Molecular Basis ◽  
Light Emission ◽  
Chemical Basis ◽  
Electronic Excited State ◽  
Colonial Form ◽  
The Common ◽  
Eighteenth And Nineteenth Centuries ◽  
Catalyzed Oxidation

The phenomenon of bioluminescence has fascinated layman and scientist alike for many centuries. During the eighteenth and nineteenth centuries a number of observations were reported on the physiology of bioluminescence in Renilla, the common sea pansy. More recently biochemists have directed their attention to the molecular basis of luminosity in this colonial form. These studies have centered primarily on defining the chemical basis for bioluminescence and its control. It is now established that bioluminescence in Renilla arises due to the luciferase-catalyzed oxidation of luciferin. This results in the creation of a product (oxyluciferin) in an electronic excited state. The transition of oxyluciferin from its excited state to the ground state leads to light emission.

scholarly journals Ultrafast Charge Recombination of Photogenerated Ion Pairs to an Electronic Excited State

2002 ◽  
Vol 106 (19) ◽  
pp. 4833-4837 ◽  
Author(s):  
Ana Morandeira ◽  
Laurine Engeli ◽  
Eric Vauthey
Keyword(s):  
Excited State ◽  
Ion Pairs ◽  
Charge Recombination ◽  
Electronic Excited State

Energy and Regge residues in quantum-mechanical ‘‘QCD’’ sum rules

1986 ◽  
Vol 33 (11) ◽  
pp. 3441-3448
Author(s):  
Bernice Durand ◽  
Loyal Durand
Keyword(s):  
Sum Rules ◽  
Quantum Mechanical ◽  
Qcd Sum Rules
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