Relaxation Mechanism of β-Carotene from S2 (1Bu+) State to S1 (2Ag–) State: Femtosecond Time-Resolved Near-IR Absorption and Stimulated Resonance Raman Studies in 900–1550 nm Region

2014 ◽  
Vol 118 (23) ◽  
pp. 4071-4078 ◽  
Author(s):  
Tomohisa Takaya ◽  
Koichi Iwata
Keyword(s):  
Resonance Raman ◽  
Relaxation Mechanism ◽  
Ir Absorption ◽  
Time Resolved ◽  
Near Ir ◽  
Β Carotene

Vibrational relaxation dynamics of β-carotene and its derivatives with substituents on terminal rings in electronically excited states as studied by femtosecond time-resolved stimulated Raman spectroscopy in the near-IR region

2018 ◽  
Vol 20 (5) ◽  
pp. 3320-3327 ◽  
Author(s):  
Tomohisa Takaya ◽  
Masato Anan ◽  
Koichi Iwata
Keyword(s):  
Raman Spectroscopy ◽  
Excited States ◽  
Vibrational Relaxation ◽  
Relaxation Dynamics ◽  
Time Resolved ◽  
Near Ir ◽  
Electronically Excited ◽  
Carbonyl Substitution ◽  
Β Carotene ◽  
Stimulated Raman

Time-resolved near-IR stimulated Raman spectroscopy indicates acceleration of vibrational relaxation in carotenoids by carbonyl substitution on their peripheral rings.

Excited-State Distortions and Electron Delocalization in Mixed-Valence Dimers:  Vibronic Analysis of the Near-IR Absorption and Resonance Raman Profiles of [Fe2(OH)3(tmtacn)2]2+

1996 ◽  
Vol 35 (15) ◽  
pp. 4323-4335 ◽  
Author(s):  
Daniel R. Gamelin ◽  
Emile L. Bominaar ◽  
Corine Mathonière ◽  
Martin L. Kirk ◽  
Karl Wieghardt ◽  
...  
Keyword(s):  
Excited State ◽  
Mixed Valence ◽  
Resonance Raman ◽  
Electron Delocalization ◽  
Ir Absorption ◽  
Near Ir ◽  
Vibronic Analysis

Plasmon-assisted interaction of Si with light, for cancer hyperthermia and electromagnetic energy harvest

2020 ◽  
Vol 92 (2) ◽  
pp. 20101
Author(s):  
Behnam Kheyraddini Mousavi ◽  
Morteza Rezaei Talarposhti ◽  
Farshid Karbassian ◽  
Arash Kheyraddini Mousavi
Keyword(s):  
Silicon Nanowires ◽  
Metallic Nanoparticles ◽  
Near Infrared ◽  
Optical Transition ◽  
Electromagnetic Energy ◽  
Energy Harvest ◽  
Absorption Enhancement ◽  
Ir Absorption ◽  
Absorption Mechanism ◽  
Near Ir

Metal-assisted chemical etching (MACE) is applied for fabrication of silicon nanowires (SiNWs). We have shown the effect of amorphous sheath of SiNWs by treating the nanowires with SF6 and the resulting reduction of absorption bandwidth, i.e. making SiNWs semi-transparent in near-infrared (IR). For the first time, by treating the fabricated SiNWs with copper containing HF∕H2O2∕H2O solution, we have generated crystalline nanowires with broader light absorption spectrum, up to λ = 1 μm. Both the absorption and photo-luminescence (PL) of the SiNWs are observed from visible to IR wavelengths. It is found that the SiNWs have PL at visible and near Infrared wavelengths, which may infer presence of mechanisms such as forbidden gap transitions other can involvement of plasmonic resonances. Non-radiative recombination of excitons is one of the reasons behind absorption of SiNWs. Also, on the dielectric metal interface, the absorption mechanism can be due to plasmonic dissipation or plasmon-assisted generation of excitons in the indirect band-gap material. Comparison between nanowires with and without metallic nanoparticles has revealed the effect of nanoparticles on absorption enhancement. The broader near IR absorption, paves the way for applications like hyperthermia of cancer while the optical transition in near IR also facilitates harvesting electromagnetic energy at a broad spectrum from visible to IR.

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