scholarly journals Near-infrared and Visible Opacities of S-type Stars: The B1Π—X1Σ+ Band System of ZrO

2021 ◽  
Vol 923 (2) ◽  
pp. 234
Author(s):  
Jason J. Sorensen ◽  
Peter F. Bernath
Keyword(s):  
Ab Initio Calculation ◽  
Optical Spectrum ◽  
Near Infrared ◽  
Spectroscopic Analysis ◽  
Band System ◽  
Transition Dipole Moment ◽  
Solar Observatory ◽  
Spectroscopic Constants ◽  
Transition Dipole ◽  
National Solar Observatory

Abstract The ZrO B1Π—X1Σ+ transition is an important opacity source in the near-infrared and optical spectrum of S-type stars. The 0–0, 0–1, 0–2, 1–0, 1–2, 1–3, 2–0, 2–1, 2–3, 2–4, 3–1, 3–4, and 4–2 bands of the 90Zr16O B1Π—X1Σ+ transition are reanalyzed using a high-temperature (2390 K) high-resolution (0.04 cm−1) emission spectrum collected at the National Solar Observatory (Kitt Peak). A modern spectroscopic analysis was performed using the PGOPHER program to provide updated spectroscopic constants and to produce a high-precision line list with line strengths based on an ab initio calculation of the transition dipole moment.

Two-Dimensional Near-Infrared and Shortwave Infrared Molecular Aggregates: Taking Kasha’s Model to the Next Dimension

2019 ◽  
Author(s):  
Arundhati Deshmukh ◽  
Danielle Koppel ◽  
Chern Chuang ◽  
Danielle Cadena ◽  
Jianshu Cao ◽  
...  
Keyword(s):  
Near Infrared ◽  
Photophysical Properties ◽  
Satellite Telemetry ◽  
Transition Dipole Moment ◽  
Short Wave ◽  
Tissue Imaging ◽  
Transition Dipole ◽  
Deep Tissue Imaging ◽  
Excitonic States ◽  
Shortwave Infrared

Technologies which utilize near-infrared (700 – 1000 nm) and short-wave infrared (1000 – 2000 nm) electromagnetic radiation have applications in deep-tissue imaging, telecommunications and satellite telemetry due to low scattering and decreased background signal in this spectral region. However, there are few molecular species, which absorb efficiently beyond 1000 nm. Transition dipole moment coupling (e.g. J-aggregation) allows for redshifted excitonic states and provides a pathway to highly absorptive electronic states in the infrared. We present aggregates of two cyanine dyes whose absorption peaks redshift dramatically upon aggregation in water from ~ 800 nm to 1000 nm and 1050 nm with sheet-like morphologies and high molar absorptivities (e ~ 10<sup>5 </sup>M<sup>-1</sup>cm<sup>-1</sup>). To describe this phenomenology, we extend Kasha’s model for J- and H-aggregation to describe the excitonic states of <i> 2-dimensional aggregates</i> whose slip is controlled by steric hindrance in the assembled structure. A consequence of the increased dimensionality is the phenomenon of an <i>intermediate </i>“I-aggregate”, one which redshifts yet displays spectral signatures of band-edge dark states akin to an H-aggregate. We distinguish between H-, I- and J-aggregates by showing the relative position of the bright (absorptive) state within the density of states using temperature dependent spectroscopy. Our results can be used to better design chromophores with predictable and tunable aggregation with new photophysical properties.

scholarly journals Design Principles for 2-Dimensional Molecular Aggregates using Kasha’s Model: Tunable Photophysics in Near and Shortwave Infrared

2019 ◽  
Author(s):  
Arundhati Deshmukh ◽  
Danielle Koppel ◽  
Chern Chuang ◽  
Danielle Cadena ◽  
Jianshu Cao ◽  
...  
Keyword(s):  
Near Infrared ◽  
Photophysical Properties ◽  
Satellite Telemetry ◽  
Transition Dipole Moment ◽  
Short Wave ◽  
Tissue Imaging ◽  
Transition Dipole ◽  
Deep Tissue Imaging ◽  
Excitonic States ◽  
Shortwave Infrared

Technologies which utilize near-infrared (700 – 1000 nm) and short-wave infrared (1000 – 2000 nm) electromagnetic radiation have applications in deep-tissue imaging, telecommunications and satellite telemetry due to low scattering and decreased background signal in this spectral region. It is therefore necessary to develop materials that absorb light efficiently beyond 1000 nm. Transition dipole moment coupling (e.g. J-aggregation) allows for redshifted excitonic states and provides a pathway to highly absorptive electronic states in the infrared. We present aggregates of two cyanine dyes whose absorption peaks redshift dramatically upon aggregation in water from ~800 nm to 1000 nm and 1050 nm respectively with sheet-like morphologies and high molar absorptivities (e ~ 10<sup>5 </sup>M<sup>-1</sup>cm<sup>-1</sup>). We use Frenkel exciton theory to extend Kasha’s model for J and H aggregation and describe the excitonic states of 2-dimensional aggregates whose slip is controlled by steric hindrance in the assembled structure. A consequence of the increased dimensionality is the phenomenon of an intermediate “I-aggregate”, one which redshifts yet displays spectral signatures of band-edge dark states akin to an H-aggregate. We distinguish between H-, I- and J-aggregates by showing the relative position of the bright (absorptive) state within the density of states using temperature dependent spectroscopy. I-aggregates hold potential for applications as charge injection moieties for semiconductors and donors for energy transfer in NIR and SWIR. Our results can be used to better design chromophores with predictable and tunable aggregation with new photophysical properties.

scholarly journals Solar 5-minute Oscillations at 2.23 μm

1994 ◽  
Vol 154 ◽  
pp. 271-276
Author(s):  
Torben Leifsen
Keyword(s):  
Time Series ◽  
Fourier Transform ◽  
Near Infrared ◽  
Broad Band ◽  
Solar Observatory ◽  
Fourier Transform Spectrometer ◽  
Large Intensity ◽  
National Solar Observatory ◽  
Long Run ◽  
The Fourier Transform

Large amplitude solar 5-min intensity oscillations have recently been detected at 2.23 μm using broad band (650 Å FWHM) photometry (Leifsen and Maltby, 1990). Large intensity amplitudes in a broad range in the near infrared was unexpected, and several questions concerning the source of the high amplitudes were raised. In an attempt to study the nature of these oscillations, time series of spectra have been obtained with the Fourier Transform Spectrometer (FTS) of the McMath telescope at National Solar Observatory at Kitt Peak. We present preliminary results from a 10 day long run in May 1991 in support for the suggestion that the results may be useful in both helio- and asteroseismological investigations.

scholarly journals Electronic structure with dipole moment and rovibrational calculations of the MgLi and MgNa molecules

2019 ◽  
Vol 97 (2) ◽  
pp. 133-144 ◽  
Author(s):  
Dunia Houalla ◽  
Sahar Kassem ◽  
Wael Chmaisani ◽  
Mahmoud Korek
Keyword(s):  
Dipole Moment ◽  
Radiative Decay ◽  
Radiative Lifetime ◽  
Line Strength ◽  
Electronic States ◽  
Transition Dipole Moment ◽  
Spectroscopic Constants ◽  
Transition Dipole ◽  
Complete Active Space ◽  
Vibrational Constants

We investigate an orderly study of the adiabatic potential energy curves for 29 and 30 low-lying 2s+1Λ+/− electronic states of the molecules MgLi and MgNa, respectively. The calculation has been done by using the complete active space self-consistent field followed by multi-reference configuration interaction with Davidson correction. For the investigated electronic states, the static and transition dipole moment curves are calculated along with the Einstein coefficients, the emission oscillator strength, the spontaneous radiative lifetime, the line strength, the classical radiative decay rate of the single-electron oscillator, the spectroscopic constants (Te, ωe, ωexe, Be, Re), and the equilibrium dissociation energy De. By means of the canonical functions approach, the ro-vibrational constants Ev, Bv, Dv, and the abscissas of the turning points, Rmin and Rmax, have been calculated for the considered electronic states up to the vibrational level v = 79. The Franck–Condon factors have been calculated and plotted for the transition between the low-lying electronic states of the two considered molecules. A good agreement is revealed between our calculated values and those available in the literature. Fifty new electronic states are investigated in the present work for the first time.

Design Principles for 2-Dimensional Molecular Aggregates using Kasha’s Model: Tunable Photophysics in Near and Shortwave Infrared

2019 ◽  
Author(s):  
Arundhati Deshmukh ◽  
Danielle Koppel ◽  
Chern Chuang ◽  
Danielle Cadena ◽  
Jianshu Cao ◽  
...  
Keyword(s):  
Near Infrared ◽  
Photophysical Properties ◽  
Satellite Telemetry ◽  
Transition Dipole Moment ◽  
Short Wave ◽  
Tissue Imaging ◽  
Transition Dipole ◽  
Deep Tissue Imaging ◽  
Excitonic States ◽  
Shortwave Infrared

Technologies which utilize near-infrared (700 – 1000 nm) and short-wave infrared (1000 – 2000 nm) electromagnetic radiation have applications in deep-tissue imaging, telecommunications and satellite telemetry due to low scattering and decreased background signal in this spectral region. It is therefore necessary to develop materials that absorb light efficiently beyond 1000 nm. Transition dipole moment coupling (e.g. J-aggregation) allows for redshifted excitonic states and provides a pathway to highly absorptive electronic states in the infrared. We present aggregates of two cyanine dyes whose absorption peaks redshift dramatically upon aggregation in water from ~800 nm to 1000 nm and 1050 nm respectively with sheet-like morphologies and high molar absorptivities (e ~ 10<sup>5 </sup>M<sup>-1</sup>cm<sup>-1</sup>). We use Frenkel exciton theory to extend Kasha’s model for J and H aggregation and describe the excitonic states of 2-dimensional aggregates whose slip is controlled by steric hindrance in the assembled structure. A consequence of the increased dimensionality is the phenomenon of an intermediate “I-aggregate”, one which redshifts yet displays spectral signatures of band-edge dark states akin to an H-aggregate. We distinguish between H-, I- and J-aggregates by showing the relative position of the bright (absorptive) state within the density of states using temperature dependent spectroscopy. I-aggregates hold potential for applications as charge injection moieties for semiconductors and donors for energy transfer in NIR and SWIR. Our results can be used to better design chromophores with predictable and tunable aggregation with new photophysical properties.

Monitoring solar activity with PEPSI

2018 ◽  
Vol 14 (A30) ◽  
pp. 351-353
Author(s):  
Ekaterina Dineva ◽  
Carsten Denker ◽  
Klaus G. Strassmeier ◽  
Ilya Ilyin ◽  
Alexei A. Pevtsov
Keyword(s):  
Solar Activity ◽  
Near Infrared ◽  
Solar Rotation ◽  
Signal To Noise Ratio ◽  
Solar Observatory ◽  
Diagnostic Tools ◽  
High Signal ◽  
The Sun ◽  
National Solar Observatory

AbstractSynoptic Sun-as-a-star observations are carried out with the Potsdam Echelle Polarimetric and Spectroscopic Instrument (PEPSI), which receives light from the Solar Disk-Integration (SDI) telescope. Daily spectra are produced with a high signal-to-noise ratio, providing access to unprecedented quasi-continuous, long-term, disk-integrated spectra of the Sun with high spectral and temporal resolution. We developed tools to monitor and study solar activity on different time-scales ranging from daily changes, over periods related to solar rotation, to annual and decadal trends. Strong chromospheric absorption lines, such as the Ca ii H & K λ3934 & 3968 Å lines, are powerful diagnostic tools for solar activity studies, since they trace the variations of the solar magnetic field. Other lines, such as Hα λ6563 Å line and the near-infrared (NIR) Ca ii λ8542 Å line, provide additional information on the physical properties in this highly complex and dynamic atmospheric layer. Currently, we work on a data pipeline for extraction, calibration, and analysis of the PEPSI/SDI data. We compare the SDI data with daily spectra from the Integrated Sunlight Spectrometer (ISS), which is part of the Synoptic Long-Term Investigation of the Sun (SOLIS) facility operated by the U.S. National Solar Observatory (NSO). This facilitates cross-calibration and validation of the SDI data.

Two-Dimensional Near-Infrared and Shortwave Infrared Molecular Aggregates: Taking Kasha’s Model to the Next Dimension

2019 ◽  
Author(s):  
Arundhati Deshmukh ◽  
Danielle Koppel ◽  
Chern Chuang ◽  
Danielle Cadena ◽  
Jianshu Cao ◽  
...  
Keyword(s):  
Near Infrared ◽  
Photophysical Properties ◽  
Satellite Telemetry ◽  
Transition Dipole Moment ◽  
Short Wave ◽  
Tissue Imaging ◽  
Transition Dipole ◽  
Deep Tissue Imaging ◽  
Excitonic States ◽  
Shortwave Infrared

Technologies which utilize near-infrared (700 – 1000 nm) and short-wave infrared (1000 – 2000 nm) electromagnetic radiation have applications in deep-tissue imaging, telecommunications and satellite telemetry due to low scattering and decreased background signal in this spectral region. However, there are few molecular species, which absorb efficiently beyond 1000 nm. Transition dipole moment coupling (e.g. J-aggregation) allows for redshifted excitonic states and provides a pathway to highly absorptive electronic states in the infrared. We present aggregates of two cyanine dyes whose absorption peaks redshift dramatically upon aggregation in water from ~ 800 nm to 1000 nm and 1050 nm with sheet-like morphologies and high molar absorptivities (e ~ 10<sup>5 </sup>M<sup>-1</sup>cm<sup>-1</sup>). To describe this phenomenology, we extend Kasha’s model for J- and H-aggregation to describe the excitonic states of <i> 2-dimensional aggregates</i> whose slip is controlled by steric hindrance in the assembled structure. A consequence of the increased dimensionality is the phenomenon of an <i>intermediate </i>“I-aggregate”, one which redshifts yet displays spectral signatures of band-edge dark states akin to an H-aggregate. We distinguish between H-, I- and J-aggregates by showing the relative position of the bright (absorptive) state within the density of states using temperature dependent spectroscopy. Our results can be used to better design chromophores with predictable and tunable aggregation with new photophysical properties.

Two-Dimensional Near-Infrared and Shortwave Infrared Molecular Aggregates: Taking Kasha’s Model to the Next Dimension

2019 ◽  
Author(s):  
Arundhati Deshmukh ◽  
Danielle Koppel ◽  
Chern Chuang ◽  
Danielle Cadena ◽  
Jianshu Cao ◽  
...  
Keyword(s):  
Near Infrared ◽  
Photophysical Properties ◽  
Satellite Telemetry ◽  
Transition Dipole Moment ◽  
Short Wave ◽  
Tissue Imaging ◽  
Transition Dipole ◽  
Deep Tissue Imaging ◽  
Excitonic States ◽  
Shortwave Infrared

Technologies which utilize near-infrared (700 – 1000 nm) and short-wave infrared (1000 – 2000 nm) electromagnetic radiation have applications in deep-tissue imaging, telecommunications and satellite telemetry due to low scattering and decreased background signal in this spectral region. However, there are few molecular species, which absorb efficiently beyond 1000 nm. Transition dipole moment coupling (e.g. J-aggregation) allows for redshifted excitonic states and provides a pathway to highly absorptive electronic states in the infrared. We present aggregates of two cyanine dyes whose absorption peaks redshift dramatically upon aggregation in water from ~ 800 nm to 1000 nm and 1050 nm with sheet-like morphologies and high molar absorptivities (e ~ 10<sup>5 </sup>M<sup>-1</sup>cm<sup>-1</sup>). To describe this phenomenology, we extend Kasha’s model for J- and H-aggregation to describe the excitonic states of <i> 2-dimensional aggregates</i> whose slip is controlled by steric hindrance in the assembled structure. A consequence of the increased dimensionality is the phenomenon of an <i>intermediate </i>“I-aggregate”, one which redshifts yet displays spectral signatures of band-edge dark states akin to an H-aggregate. We distinguish between H-, I- and J-aggregates by showing the relative position of the bright (absorptive) state within the density of states using temperature dependent spectroscopy. Our results can be used to better design chromophores with predictable and tunable aggregation with new photophysical properties.

Chemiluminescent NiO* emissions: band systems and spectral simulation

2011 ◽  
Vol 89 (8) ◽  
pp. 869-874 ◽  
Author(s):  
R.L. Gattinger ◽  
W.F.J. Evans ◽  
E.J. Llewellyn
Keyword(s):  
High Resolution ◽  
Simulation Model ◽  
Vibrational Level ◽  
Near Infrared ◽  
Band System ◽  
Spectral Band ◽  
Spectroscopic Constants ◽  
Spectral Simulation ◽  
Condon Factors ◽  
Franck Condon

Following the renewed interest in metal oxide emissions in the night airglow, high-resolution laboratory observations of NiO* in the visible and near-infrared regions of the spectrum are reviewed, and approximate spectroscopic constants are derived to augment those already available in the literature. A preliminary spectral band simulation model is developed for the relevant NiO systems. Franck–Condon factors, calculated using the preliminary spectroscopic constants, are used in the model to conduct an iterative comparison with low-resolution NiO* chemiluminescent emissions observed in the laboratory. Relative vibrational level populations are estimated, and shortcomings of the model are noted. The existence of a new NiO band system is also suggested.

scholarly journals MOLECULAR MODELING, REACTIVITY PARAMETERS AND SPECTROCHEMIC STUDIES OF ε-CAPROLACTAM AND o-PHENANTROLINE

2022 ◽  
Author(s):  
Francisco José Santos Lima ◽  
Keyword(s):  
Near Infrared ◽  
Visible Region ◽  
Transition Dipole Moment ◽  
Molar Absorptivity ◽  
Molecular Spectra ◽  
Transition Dipole ◽  
Light Emitting ◽  
Molecular Systems ◽  
Uv Visible ◽  
Molecular Compounds

In this work, molecular models were obtained, and the reactivity parameters of ε-caprolactam and ophenanthroline were calculated to evaluate the interaction in the formation of complex molecular compounds. It was observed that the main electron donor atoms, in the formation of the metal-ligand bond, are centered mainly on the oxygen and nitrogen atoms, respectively, which are sterically more favorable in these species. Conductance measurements in an aqueous solution were obtained to observe the electrolytic behavior of these compounds. Infrared spectra were also recorded to characterize vibrational transitions in identifying these species when present in complex systems. Molecular spectra of absorption in the UV-visible region were recorded to evaluate the spectrochemical properties of these individual ligands and further verify their influence on the formation of complex molecular systems. The parameters evaluated include the molar absorptivity ε, integrated absorption coefficient, oscillator force, and transition dipole moment. It was observed that the ε parameter indicates molecular transitions in the 190 – 300 nm region and the near-infrared, and the oscillator strength is typical of molecules used as dyes and sensitizers for optical light-emitting systems or light-to-electricity converters.

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