Ab-initio multireference configuration interaction and coupled cluster studies of potential surfaces for proton transfer in ammonia-proton-water hydrogen-bonded ion

1992 ◽  
Vol 96 (5) ◽  
pp. 2123-2129 ◽  
Author(s):  
S. Roszak ◽  
U. Kaldor ◽  
D. A. Chapman ◽  
Joyce J. Kaufman
Keyword(s):  
Proton Transfer ◽  
Ab Initio ◽  
Configuration Interaction ◽  
Coupled Cluster ◽  
Potential Surfaces ◽  
Water Hydrogen ◽  
Hydrogen Bonded

scholarly journals Proton Transfer from a Photoacid to Water: First Principles Simulations and Fast Fluorescence Spectroscopy

2021 ◽  
Author(s):  
Alice R. Walker ◽  
Boning Wu ◽  
Jan Meisner ◽  
Michael D. Fayer ◽  
Todd J. Martinez
Keyword(s):  
Molecular Dynamics ◽  
Excited State ◽  
Fluorescence Spectroscopy ◽  
Proton Transfer ◽  
Ab Initio ◽  
Time Constant ◽  
Emission Wavelength ◽  
Ab Initio Molecular Dynamics ◽  
Long Distance ◽  
Hydrogen Bonded

Proton transfer reactions are ubiquitous in chemistry, especially in aqueous solutions. We investigate photo-induced proton transfer between the photoacid 8-hydroxypyrene-1,3,6- trisulfonate (HPTS) and water using fast fluorescence spectroscopy and ab initio molecular dynamics simulations. Photo-excitation causes rapid proton release from the HPTS hydroxyl. Previous experiments on HPTS/water described the progress from photoexcitation to proton diffusion using kinetic equations with two time constants. The shortest time constant has been interpreted as protonated and photoexcited HPTS evolving into an “associated” state, where the proton is “shared” between the HPTS hydroxyl and an originally hydrogen bonded water. The longer time constant has been interpreted as indicating evolution to a “solvent separated” state where the shared proton undergoes long distance diffusion. In this work, we refine the previous experimental results using very pure HPTS. We then use excited state ab initio molecular dynamics to elucidate the detailed molecular mechanism of aqueous excited state proton transfer in HPTS. We find that the initial excitation results in rapid rearrangement of water, forming a strong hydrogen bonded network (a “water wire”) around HPTS. HPTS then deprotonates in ≤3 ps, resulting in a proton that migrates back and forth along the wire before localizing on a single water molecule. We find a near linear relationship between emission wavelength and proton-HPTS distance over the simulated time scale, suggesting that emission wavelength can be used as a ruler for proton distance. Our simulations reveal that the “associated” state corresponds to a water wire with a mobile proton and that the diffusion of the proton away from this water wire (to a generalized “solvent-separated” state) corresponds to the longest experimental time constant.

An ab initio study of the molecular properties of the propyne–water hydrogen-bonded complex

2007 ◽  
Vol 834-836 ◽  
pp. 258-261 ◽  
Author(s):  
Kelson C. Lopes ◽  
Regiane C.M.U. Araújo ◽  
Victor H. Rusu ◽  
Mozart N. Ramos
Keyword(s):  
Ab Initio ◽  
Molecular Properties ◽  
Ab Initio Study ◽  
Water Hydrogen ◽  
Hydrogen Bonded

Ab initio calculations on the ground and excited electronic states of neutral and charged palladium monoxide, PdO0,+,−

2018 ◽  
Vol 20 (21) ◽  
pp. 14578-14586 ◽  
Author(s):  
Nuno M. S. Almeida ◽  
Isuru R. Ariyarathna ◽  
Evangelos Miliordos
Keyword(s):  
Ab Initio Calculations ◽  
Ab Initio ◽  
Configuration Interaction ◽  
Photoelectron Spectrum ◽  
Electronic States ◽  
Reference Configuration ◽  
Coupled Cluster ◽  
Excited Electronic States ◽  
Cluster Calculations ◽  
Coupled Cluster Calculations

Multi-reference configuration interaction and coupled cluster calculations were carried out for the ground and several low-lying excited electronic states for PdO, PdO+, and PdO−. The photoelectron spectrum peaks of PdO were assigned.

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