Optical rotatory power of complex compounds. Matrix elements of the operators ∇ and (r x ∇)

Král, M.

doi:10.1135/cccc19701939

Cited by 10 publications

(5 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Let p = (ζ 1 + ζ 2 ) R /2, q = (ζ 2 − ζ 1 ) R /2, A k = w k exp(− pw ) d w and B k = w k exp(− qw ) d w . Then, following procedures described by Mulliken et al, Král, and Harada and Nakanishi, we find Equations A2 and A3 were given previously by Král …”

mentioning

confidence: 99%

Calculations of Spectroscopic Properties of the LH2 Bacteriochlorophyll−Protein Antenna Complex from Rhodopseudomonas acidophila

Alden¹,

Johnson²,

Nagarajan³

et al. 1997

J. Phys. Chem. B

271

369

View full text Add to dashboard Cite

Absorption and CD spectra of a photosynthetic bacterial antenna complex are calculated on the basis of the crystal structure of the LH2 (B800-850) complex from Rhodopseudomonas acidophila. This complex contains a ring of 18 tightly coupled bacteriochlorophylls (B850) and a ring of 9 more weakly coupled bacteriochlorophylls (B800). Molecular orbitals for bacteriochlorophylls with the three different geometries seen in the crystal structure are obtained by semiempirical quantum mechanical calculations (QCFF/PI). Exciton and charge-transfer interactions are introduced at the level of configuration interactions. Particular attention is paid to the dependence of these interactions on the interatomic distances and on dielectric screening. Absorption band shapes are treated with the aid of vibronic parameters and homogeneous line widths that have been measured by hole burning (Reddy, N. R. S., et al., Photochem. Photobiol. 1993, 57, 35-39). Inhomogeneous broadening due to diagonal disorder in the monomeric and charge-transfer transition energies is included by a Monte Carlo method. The calculations successfully reproduce the main features of measured absorption and CD spectra of the complex. The results support the view that the excited states of the B850 bacteriochlorophylls are extensively delocalized over the ring of pigments while the excited states of the B800 bacteriochlorophylls are much more localized.

show abstract

mentioning

confidence: 99%

Calculations of Spectroscopic Properties of the LH2 Bacteriochlorophyll−Protein Antenna Complex from Rhodopseudomonas acidophila

Alden¹,

Johnson²,

Nagarajan³

et al. 1997

J. Phys. Chem. B

271

369

View full text Add to dashboard Cite

show abstract

“…In fact, the combination y∂(2p z )/∂z À z∂(2p z )/∂y has exactly the same spatial distribution as 2p y [1,2]. the overlap of the two wavefunctions falls off with the interatomic distance.…”

Section: þmentioning

confidence: 87%

“…(9.32b) indicates, ℜ ex is extremely sensitive to the geometry of the dimer. It will be zero if any two of the three vectors (μ ba(1) , μ ba (2) , and R 21 ) are parallel or if all three vectors lie in the same plane.…”

Section: Circular Dichroism Of Dimers and Higher Oligomersmentioning

confidence: 99%

“…where R 21 is the vector from the center of molecule 1 to the center of molecule 2, D ba is the dipole strength of the monomeric absorption band, θ is the angle between μ ba(1) and μ ba (2) , and ϕ is the angle between R 21 and the cross product of μ ba(1) and μ ba (2) . If |R 21 | and λ ba are given in the same units (e.g., Å ) and the transition dipoles are in debyes, (1) ].…”

Section: Circular Dichroism Of Dimers and Higher Oligomersmentioning

confidence: 99%

“…the overlap of the two wavefunctions falls off with the interatomic distance. The overlap integral can be evaluated by procedures similar to those described in Box 4.11 [2]. By studying Fig.…”

Section: þmentioning

confidence: 99%

See 2 more Smart Citations

Circular Dichroism

Parson¹

2015

Modern Optical Spectroscopy

View full text Add to dashboard Cite

A simple model for the optical properties of chiral amides

Woody

1983

Biopolymers

View full text Add to dashboard Cite

SynopsisThe intramolecular charge-transfer model for the electronic structure of amides has been extended to include the effects of torsion about the peptide bond (Au = w -180) and pyramidalization at the peptide nitrogen (ON). The model is used to calculate the absorption and CD spectra of nonplanar amides as a function of the angles Au and ON. For cis-amides, the rotational strengths of the nr* and rr* transitions are much more sensitive to 8~ for a given value of Au than is the case for trans-amides. The results from the model are compared with available experimental and previous theoretical treatments of such systems. The contributions of nonplanarity in amides to the CD of various polypeptide conformations is discussed. The effects should be negligible for a-helixes but may be quite significant in P-sheets and P-turns. The CD spectrum of unordered peptides would be readily explained if there were a significant bias toward negative Aw values in polypeptides of L-amino acids. However, the evidence currently available does not indicate such a bias.

show abstract

Optical rotatory power of complex compounds. Matrix elements of the operators ∇ and (r x ∇)

Cited by 10 publications

References 0 publications

Calculations of Spectroscopic Properties of the LH2 Bacteriochlorophyll−Protein Antenna Complex from Rhodopseudomonas acidophila

Calculations of Spectroscopic Properties of the LH2 Bacteriochlorophyll−Protein Antenna Complex from Rhodopseudomonas acidophila

Circular Dichroism

A simple model for the optical properties of chiral amides

Contact Info

Product

Resources

About