Charge transfer processes in biological systems

Mason, R.

doi:10.1039/df9592700129

Cited by 27 publications

(7 citation statements)

References 3 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Besides the other evidence already mentioned for electron tunneling in molecular processes (44, 48, 49), we may cite also the observation that electron exchange takes place between gaseous ions and their neutral gaseous parent molecules over distances of approach almost twice as large as those required for momentum transfer in collisions (66,67). A correlation has been made between carcinogenicity of hydrocarbons and their fluorescence spectra which indicate a requirement that energy levels be matched (22,26). Such a requirement would be expected if the process were one of electron transfer by tunneling.…”

Section: Discussionsupporting

confidence: 59%

“…The literature was reviewed to determine what mechanisms for electron transfer have been proposed that might have some bearing on the process studied here. Szent-Gyorgyi (19) suggested that biological systems may act as semiconductors and many have followed this idea (20)(21)(22)(23)(24)(25)(26)(27)(28)(29)(30)(31). However, the measured activation energies are above 1 or 2 ev for biological material (20,(22)(23)(24)(25)(26)(27).…”

Section: Discussionmentioning

confidence: 99%

“…Szent-Gyorgyi (19) suggested that biological systems may act as semiconductors and many have followed this idea (20)(21)(22)(23)(24)(25)(26)(27)(28)(29)(30)(31). However, the measured activation energies are above 1 or 2 ev for biological material (20,(22)(23)(24)(25)(26)(27). The only organic materials with activation energies for electronic conduction in a range similar to ours are: crystalline complexes of polycyclic aromatic hydrocarbons with halogens, 0.1 ev (32); complexes of aromatic amines and halogenated quinones, 0.5 ev (33); and free radicals such as diphenyl-picryl-hydrazyl, 0.2 ev (23,25).…”

Section: Discussionmentioning

confidence: 99%

See 2 more Smart Citations

Studies of Photosynthesis Using a Pulsed Laser

Vault¹,

Chance²

1966

Biophysical Journal

471

133

View full text Add to dashboard Cite

The rate of oxidation of cytochrome following absorption of a short pulse of light from a ruby laser in the photosynthetic bacterium Chromatium has been measured spectrophotometrically. The half-time is about 2 musec at room temperature increasing to 2.3 msec at about 100 degrees K and constant at the latter value to 35 degrees K or below. The temperature dependence above 120 degrees K corresponds to an activation energy of 3.3 kcal/mole; that below 100 degrees K to less than 80 cal/mol: essentially a temperature-independent electron transport reaction. Since the slowness below 100 degrees K indicates the presence of a barrier, the lack of activation energy is taken to mean penetration by quantum-mechanical "tunneling."

show abstract

Section: Discussionsupporting

confidence: 59%

Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

See 1 more Smart Citation

Studies of Photosynthesis Using a Pulsed Laser

Vault¹,

Chance²

1966

Biophysical Journal

471

133

View full text Add to dashboard Cite

show abstract

“…Charge transfer (CT) excitation energy calculation has gained much attention in materials and biological sciences [1][2][3] . In a spatially separated donor-acceptor (D-A) system with intermolecular distance R, the CT excitation process involves electron transition from donor molecule (D) to acceptor molecule (A), and the CT excitation energy at asymptotically large R is given by…”

Section: Introductionmentioning

confidence: 99%

Charge transfer excitation energies from ground state density functional theory calculations

Mei

Yang

2019

The Journal of Chemical Physics

View full text Add to dashboard Cite

Calculating charge transfer (CT) excitation energies with high accuracy and low computational cost is a challenging task. Kohn-Sham density functional theory (KS-DFT), due to its efficiency and accuracy, has achieved great success in describing ground state problems. To extend to excited state problems, our group recently demonstrated an approach with good numerical results to calculate low-lying and Rydberg excitation energies of an N -electron system from a ground state KS or generalized KS calculations of an (N − 1)-electron system via its orbital energies.In present work, we explore further the same methodology to describe CT excitations. Numerical results from this work show that performance of conventional density functional approximations (DFAs) is not as good for CT excitations as for other excitations, due to the delocalization error. Applying localized orbital scaling correction (LOSC) to conventional DFAs, a recently developed method in our group to effectively reduce the delocalization error, can improve the results. Overall, the performance of this methodology is better than time dependant DFT (TDDFT) with conventional DFAs. In addition, it shows that results from LOSC-DFAs in this method reach similar accuracy to other methods, such as ∆SCF, G 0 W 0 with Bethe-Salpeter equations, particle-particle random phase approximation, and even high-level wavefunction method like CC2. Our analysis show that the correct 1/R trend for CT excitation can be captured from LOSC-DFA calculations, stressing that the application of DFAs with minimal delocalization error is essential within this methodology. This work provides an efficient way to calculate CT excitation energies from ground state DFT.

show abstract

“…Charge transfer (CT) excitations are frequently encountered in materials and biological sciences. [1][2][3][4] They play an important role in electron transfer and energy conversion. Therefore, it is highly desirable to understand and describe CT excitations well.…”

Section: Introductionmentioning

confidence: 99%

Charge transfer excitations from particle-particle random phase approximation—Opportunities and challenges arising from two-electron deficient systems

Yang

Domínguez

Zhang

et al. 2017

The Journal of Chemical Physics

View full text Add to dashboard Cite

The particle-particle random phase approximation (pp-RPA) is a promising method for studying charge transfer(CT) excitations. Through a detailed analysis on two-electron deficient systems, we show that the pp-RPA is always able to recover the long-distance asymptotic -1/R trend for CT excitations as a result of the concerted effect between orbital energies and the pp-RPA kernel. We also provide quantitative results for systems with relatively short donor-acceptor distances. With conventional hybrid or range-separated functionals, the pp-RPA performs much better than time-dependent density functional theory (TDDFT), although it still gives underestimated results which are not as good as TDDFT with system-dependent tuned functionals. For pp-RPA, there remain three great challenges in dealing with CT excitations. First, the delocalized frontier orbitals in strongly correlated systems often lead to difficulty with self-consistent field convergence as well as an incorrect picture with about half an electron transferred. Second, the commonly used density functionals often underestimate the energy gap between the highest occupied molecular orbital and the lowest unoccupied molecular orbital (LUMO) for the two-electron deficient species, resulting in systems with delocalized orbitals. Third, the performance of pp-RPA greatly depends on the energy difference between the LUMO and a higher virtual orbital. However, the meaning of the orbital energies for higher virtual orbitals is still not clear. We also discuss the performance of an approximate pp-RPA scheme that uses density functional tight binding (pp-DFTB) as reference and demonstrate that the aforementioned challenges can be overcome by adopting suitable range-separated hybrid functionals. The pp-RPA and pp-DFTB are thus promising general approaches for describing charge transfer excitations.

show abstract

Charge transfer processes in biological systems

Cited by 27 publications

References 3 publications

Studies of Photosynthesis Using a Pulsed Laser

Studies of Photosynthesis Using a Pulsed Laser

Charge transfer excitation energies from ground state density functional theory calculations

Charge transfer excitations from particle-particle random phase approximation—Opportunities and challenges arising from two-electron deficient systems

Contact Info

Product

Resources

About