Combining Electronic Structure Methods with the Calculation of Hydrogen Vibrational Wavefunctions:  Application to Hydride Transfer in Liver Alcohol Dehydrogenase

2000 ◽  
Vol 104 (37) ◽  
pp. 8884-8894 ◽  
Author(s):  
Simon P. Webb ◽  
Pratul K. Agarwal ◽  
Sharon Hammes-Schiffer
Keyword(s):  
Electronic Structure ◽  
Alcohol Dehydrogenase ◽  
Hydride Transfer ◽  
Liver Alcohol Dehydrogenase ◽  
Electronic Structure Methods

Hydride Transfer in Liver Alcohol Dehydrogenase:  Quantum Dynamics, Kinetic Isotope Effects, and Role of Enzyme Motion

2001 ◽  
Vol 123 (45) ◽  
pp. 11262-11272 ◽  
Author(s):  
Salomon R. Billeter ◽  
Simon P. Webb ◽  
Pratul K. Agarwal ◽  
Tzvetelin Iordanov ◽  
Sharon Hammes-Schiffer
Keyword(s):  
Alcohol Dehydrogenase ◽  
Quantum Dynamics ◽  
Isotope Effects ◽  
Hydride Transfer ◽  
Kinetic Isotope Effects ◽  
Liver Alcohol Dehydrogenase ◽  
Kinetic Isotope

EXAFS INVESTIGATION OF THE STRUCTURAL SITE OF LIVER ALCOHOL DEHYDROGENASE

1986 ◽  
Vol 47 (C8) ◽  
pp. C8-1165-C8-1168
Author(s):  
M. ZEPPEZAUER ◽  
C. HAAS ◽  
W. MARET ◽  
C. HERMES ◽  
R. F. PETTIFER
Keyword(s):  
Alcohol Dehydrogenase ◽  
Liver Alcohol Dehydrogenase ◽  
Structural Site

Performance of Electronic Structure Methods for the Description of Hückel-Möbius Interconversions in Extended π-Systems

2019 ◽  
Author(s):  
Tatiana Woller ◽  
Ambar Banerjee ◽  
Nitai Sylvetsky ◽  
Xavier Deraet ◽  
Frank De Proft ◽  
...  
Keyword(s):  
Electronic Structure ◽  
Basis Set ◽  
Dft Methods ◽  
Molecular Switching ◽  
Wide Range ◽  
Electronic Structure Methods ◽  
Explicitly Correlated ◽  
Relative Errors ◽  
The Stability ◽  
Basis Set Expansion

<p>Expanded porphyrins provide a versatile route to molecular switching devices due to their ability to shift between several π-conjugation topologies encoding distinct properties. Taking into account its size and huge conformational flexibility, DFT remains the workhorse for modeling such extended macrocycles. Nevertheless, the stability of Hückel and Möbius conformers depends on a complex interplay of different factors, such as hydrogen bonding, p···p stacking, steric effects, ring strain and electron delocalization. As a consequence, the selection of an exchange-correlation functional for describing the energy profile of topological switches is very difficult. For these reasons, we have examined the performance of a variety of wavefunction methods and density functionals for describing the thermochemistry and kinetics of topology interconversions across a wide range of macrocycles. Especially for hexa- and heptaphyrins, the Möbius structures have a pronouncedly stronger degree of static correlation than the Hückel and figure-eight structures, and as a result the relative energies of singly-twisted structures are a challenging test for electronic structure methods. Comparison of limited orbital space full CI calculations with CCSD(T) calculations within the same active spaces shows that post-CCSD(T) correlation contributions to relative energies are very minor. At the same time, relative energies are weakly sensitive to further basis set expansion, as proven by the minor energy differences between MP2/cc-pVDZ and explicitly correlated MP2-F12/cc-pVDZ-F12 calculations. Hence, our CCSD(T) reference values are reasonably well-converged in both 1-particle and n-particle spaces. While conventional MP2 and MP3 yield very poor results, SCS-MP2 and particularly SOS-MP2 and SCS-MP3 agree to better than 1 kcal mol<sup>-1</sup> with the CCSD(T) relative energies. Regarding DFT methods, only M06-2X provides relative errors close to chemical accuracy with a RMSD of 1.2 kcal mol<sup>-1</sup>. While the original DSD-PBEP86 double hybrid performs fairly poorly for these extended p-systems, the errors drop down to 2 kcal mol<sup>-1</sup> for the revised revDSD-PBEP86-NL, again showing that same-spin MP2-like correlation has a detrimental impact on performance like the SOS-MP2 results. </p>

Ideal–Gas Thermochemical Properties for Alkanolamine and Related Species Involved in Carbon Capture Applications

2020 ◽  
Author(s):  
Nayyereh hatefi ◽  
William Smith
Keyword(s):  
Heat Capacity ◽  
Electronic Structure ◽  
Co2 Capture ◽  
Carbon Capture ◽  
Ideal Gas ◽  
Thermochemical Properties ◽  
Temperature Range ◽  
Comparison Results ◽  
Electronic Structure Methods ◽  
Protonated Forms

<div>Ideal{gas thermochemical properties (enthalpy, entropy, Gibbs energy, and heat capacity, Cp) of 49 alkanolamines potentially suitable for CO2 capture applications and their carbamate and protonated forms were calculated using two high{order electronic structure methods, G4 and G3B3 (or G3//B3LYP). We also calculate for comparison results from the commonly used B3LYP/aug-cc-pVTZ method. This data is useful for the construction of molecular{based thermodynamic models of CO2 capture processes involving these species. The Cp data for each species over the temperature range 200 K{1500 K is presented as functions of temperature in the form of NASA seven-term polynomial expressions, permitting the set of thermochemical properties to be calculated over this temperature range. The accuracy of the G3B3 and G4 results is estimated to be 1 kcal/mol and the B3LYP/aug-cc-pVTZ results are of nferior quality..</div>

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