scholarly journals Nitrile IR intensities characterize electric fields and hydrogen bonding in protic, aprotic, and protein environments

2022 ◽  
Author(s):  
Jared Bryce Weaver ◽  
Jacek Kozuch ◽  
Jacob M. Kirsh ◽  
Steven G. Boxer
Keyword(s):  
Hydrogen Bonding ◽  
Dipole Moment ◽  
Electric Fields ◽  
Stark Effect ◽  
Transition Dipole Moment ◽  
Transition Dipole ◽  
Integrated Intensity ◽  
Ir Frequencies ◽  
Semi Empirical ◽  
Ir Intensities

Nitriles are widely used as vibrational probes; however, the interpretation of their IR frequencies is complicated by hydrogen bonding (H-bonding) in protic environments. We report a new vibrational Stark effect (VSE) that correlates the electric field projected on the nitrile bond to the transition dipole moment and, by extension, the nitrile peak area or integrated intensity. This linear VSE applies to both H-bonding and non-H-bonding interactions. It can therefore be generally applied to determine electric fields in all environments. Additionally, it allows for semi-empirical extraction of the H-bonding contribution to the blueshift of the nitrile frequency. Nitriles were incorporated at H-bonding and non-H-bonding protein sites using amber suppression, and each nitrile variant was structurally characterized at high resolution. We exploited the combined information now available from variations in frequency and integrated intensity and demonstrate that nitriles are a generally useful probe for electric fields.

Theoretical studies on the one- and two-photon absorption of tetrabenzoporphyrins and phthalocyanines

2004 ◽  
Vol 82 (1) ◽  
pp. 19-26 ◽  
Author(s):  
Xin Zhou ◽  
Ai-Min Ren ◽  
Ji-Kang Feng ◽  
Xiao-Juan Liu
Keyword(s):  
Dipole Moment ◽  
Cross Sections ◽  
Density Functional ◽  
Transition Dipole Moment ◽  
Photon Absorption ◽  
Transition Dipole ◽  
Two Photon Absorption ◽  
Two Photon ◽  
Order Of Magnitude ◽  
The One

The one-photon absorption (OPA) properties of tetrabenzoporphyrins (TBPs) and phthalocyanines (Pcs) were studied using the semiempirical ZINDO method and time-dependent density functional theory (TDDFT), respectively. The compared results confirmed that the semiempirical ZINDO method was reasonably reliable when calculating the OPA of tetrabenzoporphyrins and phthalocyanines. On the basis of the OPA properties obtained from the ZINDO method, two-photon absorption (TPA) properties of two series of molecules were investigated, using ZINDO and sum-over-states (SOS) methods. The results showed that the TPA cross-sections of all molecules were in the range of 220.6 × 10–50 – 345.9 × 10–50 cm4·s·photon–1, which were in the same order of magnitude as the values reported in the literature. The relatively larger δ(ω) value for Pcs with respect to that for corresponding TBPs originates from larger intramolecular charge transfer, which can be characterized by the difference of dipole moment between S0 and S1 and the transition dipole moment between S1 and S5.Key words: two-photon absorption, ZINDO, sum-over-states, tetrabenzoporphyrin, phthalocyanines.

Lifetimes and transition dipole moment functions of NaK low lying singlet states: Empirical and ab initio approach

1998 ◽  
Vol 109 (16) ◽  
pp. 6725-6735 ◽  
Author(s):  
M. Tamanis ◽  
M. Auzinsh ◽  
I. Klincare ◽  
O. Nikolayeva ◽  
R. Ferber ◽  
...  
Keyword(s):  
Dipole Moment ◽  
Ab Initio ◽  
Transition Dipole Moment ◽  
Transition Dipole ◽  
Singlet States ◽  
Moment Functions ◽  
Ab Initio Approach

Fundamental Absorption Band of HD

1974 ◽  
Vol 52 (17) ◽  
pp. 1669-1671 ◽  
Author(s):  
J. Bejar ◽  
H. P. Gush
Keyword(s):  
Dipole Moment ◽  
Absorption Band ◽  
Line Width ◽  
Doppler Effect ◽  
Transition Dipole Moment ◽  
Vibration Band ◽  
Transition Dipole ◽  
Fundamental Absorption Band ◽  
The Doppler Effect

The fundamental rotation–vibration band of HD has been resolved in the gas at 1 atm pressure. The line width appears to be totally due to the Doppler effect and equals 0.026 cm−1. The transition dipole moment has been calculated from the intensities of lines in the R branch: it is found to vary from 4 × 10−5 D for J = 0 to 7 × 10−5 for J = 4.

Quantum yield in blue-emitting anthracene derivatives: vibronic coupling density and transition dipole moment density

2014 ◽  
Vol 16 (27) ◽  
pp. 14244-14256 ◽  
Author(s):  
Motoyuki Uejima ◽  
Tohru Sato ◽  
Daisuke Yokoyama ◽  
Kazuyoshi Tanaka ◽  
Jong-Wook Park
Keyword(s):  
Dipole Moment ◽  
Quantum Yield ◽  
Transition Dipole Moment ◽  
Vibronic Coupling ◽  
Transition Dipole ◽  
Anthracene Derivatives ◽  
Vibronic Couplings ◽  
Franck Condon

Diagonal vibronic couplings in the Franck–Condon S1 state cause torsional distortion, which gives rise to enhancement of fluorescence with a large transition dipole moment.

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