scholarly journals Ultrafast Vibrational Dynamics of CO Ligands on RuTPP/Cu(110) under Photodesorption Conditions

Surfaces ◽  
2019 ◽  
Vol 2 (1) ◽  
pp. 117-130 ◽  
Author(s):  
Takuma Omiya ◽  
Yousoo Kim ◽  
Rasmita Raval ◽  
Heike Arnolds
Keyword(s):  
Low Frequency ◽  
Blue Shift ◽  
Vibrational Modes ◽  
Vibrational Dynamics ◽  
Sum Frequency ◽  
Stretching Vibration ◽  
A Charge ◽  
Anharmonic Coupling ◽  
Vibration Coupling ◽  
Probe Spectroscopy

We have studied CO coordinated to ruthenium tetraphenylporphyrin (RuTPP)/Cu(110) and directly adsorbed to Cu(110), using femtosecond pump-sum frequency probe spectroscopy, to alter the degree of electron-vibration coupling between the metal substrate and CO. We observe the facile femtosecond laser-induced desorption of CO from RuTPP/Cu(110), but not from Cu(110). A change in the vibrational transients, in the first few picoseconds, from a red- to blue-shift of the C–O stretching vibration under photodesorption conditions, was also observed. This drastic change can be explained, if the cause of the C–O frequency redshift of Cu(110) is not the usually-assumed anharmonic coupling to low frequency vibrational modes, but a charge transfer from hot electrons to the CO 2π* state. This antibonding state shifts to higher energies on RuTPP, removing the C–O redshift and, instead, reveals a blueshift, predicted to arise from electron-mediated coupling between the coherently excited internal stretch and low frequency modes in the system.

Vibrational dynamics of the CO stretching of 9-fluorenone studied by visible-pump and infrared-probe spectroscopy

2015 ◽  
Vol 177 ◽  
pp. 65-75 ◽  
Author(s):  
Yuki Fukui ◽  
Kaoru Ohta ◽  
Keisuke Tominaga
Keyword(s):  
Low Frequency ◽  
Spectral Shift ◽  
Vibrational Dynamics ◽  
Electronically Excited State ◽  
Protic Solvents ◽  
Electronically Excited ◽  
Probe Spectroscopy ◽  
Hydrogen Bond Dynamics ◽  
Solvent Complex ◽  
Anharmonic Couplings

We studied the effects of hydrogen bonds on the vibrational structures and vibrational dynamics of the CO stretching mode of 9-fluorenone (FL) in the electronically excited state in aprotic and protic solvents using sub-picosecond visible-pump and IR-probe spectroscopy. The transient IR spectrum of the CO stretching band in methanol-d4 has two bands at 1529.9 cm−1 and 1543.4 cm−1, which are assigned to an FL-solvent complex and free FL, respectively. In the aprotic solvents, the CO stretching bands show blue-shifts in time. This shift is due to vibrational cooling, which is derived from anharmonic couplings with some low-frequency modes. Interestingly, a red-shift is observed at later delay time for the band at 1529.9 cm−1 in methanol-d4. A possible mechanism of this spectral shift is related to the hydrogen bond dynamics between the solute and solvent.

scholarly journals Time-Resolved Terahertz Spectroscopy of Condensed Phase Reactions

1999 ◽  
Vol 19 (1-4) ◽  
pp. 145-148
Author(s):  
Richard McElroy ◽  
Klaas Wynne
Keyword(s):  
Terahertz Spectroscopy ◽  
Low Frequency ◽  
Electronic States ◽  
Carrier Dynamics ◽  
Solvation Dynamics ◽  
Vibrational Modes ◽  
Time Resolved ◽  
Condensed Phase Reactions ◽  
Probe Spectroscopy ◽  
First Time

Ultrafast time-resolved visible-pump, far-IR (THz) probe spectroscopy has been developed in our lab and has been applied to study carrier dynamics in photoexcited GaAs and dipole solvation dynamics in betaine and p-nitroaniline. This type of spectroscopy enables us to study for the first time the nonequilibrium interaction between excited electronic states and low frequency vibrational modes.

scholarly journals Sum frequency generation spectroscopy probing of formation of self-assembled monolayers from thiols with terminal phenylalanine ring and intrachain amide groups

Chemija ◽  
2018 ◽  
Vol 29 (4) ◽  
Author(s):  
Marija Špandyreva ◽  
Ilja Ignatjev ◽  
Ieva Matulaitienė ◽  
Zenonas Kuodis ◽  
Gediminas Niaura
Keyword(s):  
Low Frequency ◽  
Sum Frequency Generation ◽  
Self Assembled Monolayer ◽  
Sum Frequency ◽  
Sum Frequency Generation Spectroscopy ◽  
Assembled Monolayers ◽  
Stretching Vibration ◽  
Polycrystalline Gold ◽  
Self Assembled ◽  
Frequency Generation

Formation of a self-assembled monolayer onto the polycrystalline gold substrate from thiols containing a terminal phenylalanine (Phe) ring and intrachain amide groups (HS-(CH2)7-CONH-(CH2)2-C6H5) was characterized by vibrational sum frequency generation (SFG) spectroscopy. The temporal evolution of the characteristic Phe ring stretching vibration ν(=C–H) near 3069 cm–1 and the Amide A mode were monitored by nonlinear vibrational spectroscopy. The SFG data revealed the complete ordering of the terminal Phe rings after about 60 min of adsorption. Formation of a strong hydrogen bonding between the adjacent chains of adsorbed molecules was evident by appearance of the Amide A mode at the relative low frequency (3280–3308 cm–1). The well-ordered and strongly hydrogen bonded SAM with the terminal Phe ring functionality is a promising platform for the analysis of interactions and the function of aromatic rings in biomolecular processes.

Study on Raman Spectra of Zinc Gluconate under Effect of Different Solvent

2013 ◽  
Vol 552 ◽  
pp. 111-114
Author(s):  
Xiu Ping Sun ◽  
Zai Chao Yu
Keyword(s):  
Raman Spectrum ◽  
Raman Spectra ◽  
Low Frequency ◽  
Blue Shift ◽  
Structure Change ◽  
Molecular Vibration ◽  
Polar Solvents ◽  
Zinc Gluconate ◽  
Stretching Vibration ◽  
Butanol Solution

Raman spectrum is a kind of characteristic spectrum. The information of molecular vibration and rotation can be obtained by studying Raman spectrum. Raman spectrum will be changed because of molecular interaction under effect of different solvent. We selected zinc gluconate as the object of research. Zinc gluconate is dissolved respectively in ethyl chloride, benzene, ring of ethane，chloroform, acetic acid, ethylene oxide, n-propanol, n-butanol solution, and Raman spectra were tested. The change of molecular internal structure and the interaction of molecular functional groups are studied by means of measuring Raman frequency shift, bandwidth, and light intensity. Thus, the information of solute structure change can be obtained. Experiments show that when zinc gluconate dissolved in the organic solvent, molecular gap became larger, its velocity increased, and stretching vibration of associating OH key group became strong. Methylenes in polar and non-polar molecule interact, and the polarization changed. In different polar solvents, Raman spectra had different changes. When the bond length increases，the stretching vibration frequency of molecules moves to the direction of low frequency. It produces red shift instead of blue shift. The results of this paper provide a basis to study molecular interactions further.

Temperature Dependence of the Air/Water Interface Revealed by Polarization Sensitive Sum-Frequency Generation Spectroscopy

2018 ◽  
Author(s):  
Daniel R. Moberg ◽  
Shelby C. Straight ◽  
Francesco Paesani
Keyword(s):  
Temperature Dependence ◽  
Low Frequency ◽  
Potential Energy Function ◽  
Md Simulations ◽  
Sum Frequency Generation ◽  
Water Molecules ◽  
Water Interface ◽  
Sum Frequency ◽  
Air Water Interface ◽  
Frequency Generation

<div> <div> <div> <p>The temperature dependence of the vibrational sum-frequency generation (vSFG) spectra of the the air/water interface is investigated using many-body molecular dynamics (MB-MD) simulations performed with the MB-pol potential energy function. The total vSFG spectra calculated for different polarization combinations are then analyzed in terms of molecular auto-correlation and cross-correlation contributions. To provide molecular-level insights into interfacial hydrogen-bonding topologies, which give rise to specific spectroscopic features, the vSFG spectra are further investigated by separating contributions associated with water molecules donating 0, 1, or 2 hydrogen bonds to neighboring water molecules. This analysis suggests that the low frequency shoulder of the free OH peak which appears at ∼3600 cm−1 is primarily due to intermolecular couplings between both singly and doubly hydrogen-bonded molecules. </p> </div> </div> </div>

scholarly journals Low frequency vibrational modes of oxygenated myoglobin, hemoglobins, and modified derivatives.

1994 ◽  
Vol 269 (49) ◽  
pp. 31047-31050
Author(s):  
S Jeyarajah ◽  
L M Proniewicz ◽  
H Bronder ◽  
J R Kincaid
Keyword(s):  
Low Frequency ◽  
Vibrational Modes

scholarly journals Moduli and modes in the Mikado model

Soft Matter ◽  
2021 ◽  
Author(s):  
Brian Tighe ◽  
Karsten Baumgarten
Keyword(s):  
Shear Modulus ◽  
Mechanical Model ◽  
Low Frequency ◽  
Vibrational Modes ◽  
Prior Work ◽  
Fiber Networks ◽  
Elastic Shear Modulus ◽  
Flexible Fiber ◽  
Elastic Shear

We determine how low frequency vibrational modes control the elastic shear modulus of Mikado networks, a minimal mechanical model for semi-flexible fiber networks. From prior work it is known that...

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