Infrared Band Progressions in the CH2 Scissoring Region and the Ring Puckering Vibration of Trimethylene Oxide and some Deuterated Analogs

1972 ◽  
Vol 50 (17) ◽  
pp. 2761-2770 ◽  
Author(s):  
H. Wieser ◽  
M. Danyluk

Band progressions have been observed in the CH2 scissoring region of the i.r. spectra of trimethylene oxide (C3H6O) and three of its deuterated analogs (α-d2, β-d2, and α,α′-d4). With the aid of the pure ring puckering transitions (published previously) and a simple theoretical model of puckering–vibrational interactions the absorptions have been assigned to combination tones of CH2 scissoring vibrations with the ring puckering mode and its overtones. The scissoring fundamentals of the α- and β-methylene groups have been identified and assigned. Of all the vibrations for which combination progressions are observed, only the β-CH2 scissoring mode of the normal compound exhibits significant differences between the ring puckering transitions in the ground state and the vibrational excited state.

Author(s):  
Ben O. Spurlock ◽  
Milton J. Cormier

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.


1996 ◽  
Vol 6 (9) ◽  
pp. 1167-1180 ◽  
Author(s):  
A. Gicquel ◽  
M. Chenevier ◽  
Y. Breton ◽  
M. Petiau ◽  
J. P. Booth ◽  
...  

2020 ◽  
Author(s):  
Tomislav Rovis ◽  
Benjamin D. Ravetz ◽  
Nicholas E. S. Tay ◽  
Candice Joe ◽  
Melda Sezen-Edmonds ◽  
...  

We describe a new family of catalysts that undergo direct ground state singlet to excited state triplet excitation with IR light, leading to photoredox catalysis without the energy waste associated with intersystem crossing. The finding allows a mole scale reaction in batch using infrared irradiation.


2019 ◽  
Author(s):  
Matthew M. Brister ◽  
Carlos Crespo-Hernández

<p></p><p> Damage to RNA from ultraviolet radiation induce chemical modifications to the nucleobases. Unraveling the excited states involved in these reactions is essential, but investigations aimed at understanding the electronic-energy relaxation pathways of the RNA nucleotide uridine 5’-monophosphate (UMP) have not received enough attention. In this Letter, the excited-state dynamics of UMP is investigated in aqueous solution. Excitation at 267 nm results in a trifurcation event that leads to the simultaneous population of the vibrationally-excited ground state, a longlived <sup>1</sup>n<sub>O</sub>π* state, and a receiver triplet state within 200 fs. The receiver state internally convert to the long-lived <sup>3</sup>ππ* state in an ultrafast time scale. The results elucidate the electronic relaxation pathways and clarify earlier transient absorption experiments performed for uracil derivatives in solution. This mechanistic information is important because long-lived nπ* and ππ* excited states of both singlet and triplet multiplicities are thought to lead to the formation of harmful photoproducts.</p><p></p>


2020 ◽  
Vol 0 (0) ◽  
Author(s):  
Riccardo Camboni ◽  
Paola Valbonesi

AbstractWe empirically investigate incumbents’ and entrants’ bids on an original dataset of 192 scoring rule auctions for canteen services in Italy. Our findings show that winning rebates are lower (i.e., prices paid by the public buyer are higher) when the contract is awarded to the incumbent supplier. This result is not explained by the observable characteristics of the auction or the service awarded. We develop a simple theoretical model showing that the result is consistent with a setting in which the buyer exploits specific information on the incumbent supplier’s production cost.


Entropy ◽  
2021 ◽  
Vol 23 (8) ◽  
pp. 1007
Author(s):  
Michał Ramsza

The present paper reports simulation results for a simple model of reference group influence on market choices, e.g., brand selection. The model was simulated on three types of random graphs, Erdos–Renyi, Barabasi–Albert, and Watts–Strogatz. The estimates of equilibria based on the simulation results were compared to the equilibria of the theoretical model. It was verified that the simulations exhibited the same qualitative behavior as the theoretical model, and for graphs with high connectivity and low clustering, the quantitative predictions offered a viable approximation. These results allowed extending the results from the simple theoretical model to networks. Thus, by increasing the positive response towards the reference group, the third party may create a bistable situation with two equilibria at which respective brands dominate the market. This task is easier for large reference groups.


2021 ◽  
Vol 23 (14) ◽  
pp. 8525-8540
Author(s):  
Mudong Feng ◽  
Michael K. Gilson

Ground-state and excited-state molecular dynamics simulations shed light on the rotation mechanism of small, light-driven molecular motors and predict motor performance. How fast can they rotate; how much torque and power can they generate?


1990 ◽  
Vol 26 (5) ◽  
pp. 320 ◽  
Author(s):  
M. Monerie ◽  
T. Georges ◽  
P.L. Francois ◽  
J.Y. Allain ◽  
D. Neveux

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