scholarly journals Excited States of Gold(I) Compounds, Luminescence and Gold-Gold Bonding

1994 ◽  
Vol 1 (5-6) ◽  
pp. 459-466 ◽  
Author(s):  
John P. Fackler ◽  
Zerihun Assefa ◽  
Jennifer M. Forward ◽  
Richard J. Staples
Keyword(s):  
Aqueous Solution ◽  
Excited State ◽  
Triplet State ◽  
Excited States ◽  
Ground State ◽  
Superoxide Anion ◽  
Direct Interaction ◽  
Water Soluble ◽  
State Behavior ◽  
Β Carotene

It has long been established by Khan that the superoxide anion, O2-, generates singlet oxygen, O21Δg, during dismutation. Auranofin, gold-phosphine thiols, β-Carotene, and metal-sulfur compounds can rapidly quench singlet O2. The quenching of the O21Δg, which exists at 7752 cm-1 above the ground state triplet, may be due to the direct interaction of the singlet O2 with gold(I) or may require special ligands such as those containing sulfur coordinated to the metal. Thus we have been examining the excited state behavior of gold(I) species and the mechanisms for luminescence. Luminescence is observed under various conditions, with visible emission ranging from blue to red depending on the ligands coordinated to gold(I). Triplet state emission can be found from mononuclear three coordinate Au(I) species, including species which display this behavior in aqueous solution. A description is given of the luminescent three coordinate TPA (triazaphosphaadamantane) and TPPTS (triphenylphosphine-trisulfonate) complexes, the first examples of water soluble luminescent species of gold(I).

Excited-State Dynamics in the RNA Nucleotide Uridine 5’-Monophosphate Investigated by Femtosecond Broadband Transient Absorption Spectroscopy

2019 ◽  
Author(s):  
Matthew M. Brister ◽  
Carlos Crespo-Hernández
Keyword(s):  
Excited State ◽  
Excited States ◽  
Ground State ◽  
Transient Absorption ◽  
Electronic Energy ◽  
Transient Absorption Spectroscopy ◽  
Electronic Relaxation ◽  
Vibrationally Excited ◽  
Excited State Dynamics ◽  
Π State

<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>

A water soluble ESIPT-based fluorescent chemodosimeter for the ratiometric detection of palladium ions in aqueous solution and its application in live-cell imaging

2018 ◽  
Vol 42 (19) ◽  
pp. 15587-15592 ◽  
Author(s):  
Jing Huang ◽  
Yu Ding ◽  
Hongyu Fu ◽  
Bo Chen ◽  
Yifeng Han
Keyword(s):  
Aqueous Solution ◽  
Excited State ◽  
Proton Transfer ◽  
Live Cell Imaging ◽  
Cell Imaging ◽  
Intramolecular Proton Transfer ◽  
Live Cell ◽  
Water Soluble ◽  
Ratiometric Detection ◽  
Fluorescent Chemodosimeter

A new Excited State Intramolecular Proton Transfer (ESIPT) based water-soluble fluorescent chemodosimeter for the ratiometric detection of palladium ions has been rationally designed and developed.

scholarly journals Photophysics of a copper phenanthroline elucidated by trajectory and wavepacket-based quantum dynamics: a synergetic approach

2017 ◽  
Vol 19 (30) ◽  
pp. 19590-19600 ◽  
Author(s):  
G. Capano ◽  
T. J. Penfold ◽  
M. Chergui ◽  
I. Tavernelli
Keyword(s):  
Molecular Dynamics ◽  
Excited State ◽  
Excited States ◽  
Ground State ◽  
Quantum Dynamics ◽  
Equilibrium Processes ◽  
Valuable Method ◽  
Non Equilibrium

On-the-fly excited state molecular dynamics is a valuable method for studying non-equilibrium processes in excited states and is beginning to emerge as a mature approach much like its ground state counterparts.

scholarly journals Measurements of n?g Coincidences in the Reaction 10B (d, n?)11C

1960 ◽  
Vol 13 (2) ◽  
pp. 99 ◽  
Author(s):  
JA McDonell ◽  
DG Sargood ◽  
JR Moroney ◽  
JR Prescott
Keyword(s):  
Excited State ◽  
Excited States ◽  
Ground State ◽  
State Transitions

The energies of some neutron groups leading to low excited states of "C in the reaction lOB(d,ny)"C have been measured. These lead to values of 4�3�0�3 MeV and 6�53 � O' 02 MeV for the energies of the second and fourth excited states respectively. y-Ray spectra have also been studied in coincidence with different neutron groups. Ground state transitions were observed from the second, third, and fourth excited states, together with cascade decays of the fourth excited state through each of the second and third. Deductions from these y-ray spectra considerably reduce the number of spin possibilities which have been found for these levels by other workers.

scholarly journals Study of Millimeter-Wave Rotational Spectra ofTrioxane in Ground, v(A), v1(E) = 1 and v2(E) = 1 States

2009 ◽  
Vol 6 (s1) ◽  
pp. S259-S279 ◽  
Author(s):  
Masoud Motamedi ◽  
Najmehalsadat Khademi
Keyword(s):  
Excited State ◽  
Excited States ◽  
Millimeter Wave ◽  
Ground State ◽  
Vibrational States ◽  
Rotational Spectra ◽  
First Time

The millimeter-wave rotational spectra of the ground and excited vibrational states v(A), v1(E) =1 and v2(E ) =1 of the oblate symmetric top molecule, (CH2O)3, have been analyzed again. The B0= 5273.25747MHz, DJ= 1.334547 kHz, DJk= -2.0206 kHz, HJ(-1.01 mHz), HJK(-3.80 mHz), and HKJ(4.1 mHz) have been determined for ground state. For non degenerate excited state, vA(1), the B = 5260.227723 MHz and DJand DJKwere determined 1.27171 kHz and -1.8789 kHz respectively. The 1=±1 series have been assigned in two different excited states v1(E) =1 and v2(E) =1.Most of the parameters were determined with higher accuracy compare with before. For the v2(E) =1 state the Cζ=-1940.54(11) MHz and qJ= 0.0753 (97) kHz were determined for the first time.

Determination of Ionization Efficiencies of Excited Atoms in a Flame by Laser-Enhanced Ionization Spectrometry

1989 ◽  
Vol 43 (6) ◽  
pp. 940-952 ◽  
Author(s):  
O. Axner ◽  
T. Berglind
Keyword(s):  
Excited State ◽  
Excited States ◽  
Ground State ◽  
Energy Difference ◽  
Ionization Efficiency ◽  
Striking Feature ◽  
Boltzmann Factor ◽  
Excited Atoms ◽  
Ionization Limit

State-specific ionization efficiencies for excited Li and Na atoms in acetylene/air flames have been determined. The ionization efficiencies, i.e., the probability that the excited atoms ionize instead of returning to the ground state, are determined by relating collision-assisted Laser-Enhanced Ionization (LEI) signals from various excited states with laser-induced photoionization signals. The ionization efficiencies are found to decrease (from being one at the ionization limit) almost monotonically as the lower atoms are excited. The most striking feature, however, is that the decrease of the ionization efficiency values is generally found to be less than the decrease of the Boltzmann factor, exp(- δE/kT), when the energy difference, δE, between the excited state and the ionization limit is increased. The ionization efficiencies are found to be close to unity for states with δE < kT and approximately 50% for states with δE ≈ 2.5 kT ( np ≈ 6 p). For the lower states, the ionization efficiencies are found to be approximately five times larger than the Boltzmann factor.

Theoretical Study of Density Function Theory on Excited States of Methyl Methacrylate

2011 ◽  
Vol 233-235 ◽  
pp. 2871-2874
Author(s):  
Zhi Xong Huang ◽  
Gang Qin ◽  
Ming Zhang ◽  
Yan Qin ◽  
Lian Meng Zhang
Keyword(s):  
Excited State ◽  
Methyl Methacrylate ◽  
Excitation Energy ◽  
Excited States ◽  
Ground State ◽  
Theoretical Study ◽  
Function Theory ◽  
Density Function Theory ◽  
Molecular Structures ◽  
Homo And Lumo

The excited states of methyl methacrylate(MMA) were calculated by CIS method, MMA molecules on the ground and excited states of molecular structures were optimized. The HOMO and LUMO molecular orbitals of MMA molecule are given in the ground state and excited state . The results show that: MMA is excited, the molecular orbital from 27 → 28, the excitation energy is 1.4310eV, Carbon-carbon（C=C）double bonds break.

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