Recherche

Afficher tous les résultats pour

Accueil

Personne

Thomas Rizzo

À propos
Confidentialité
Mentions légales

Graph Chatbot

Publications associées (100)

Spectroscopy and Conformational Preferences of Gas-Phase Helices

Oleg Boyarkine, Thomas Rizzo, Caroline Seaiby

We describe here a study of the spectroscopy of two peptides that we expect to be helical, Ac-Phe-(Ala)5-Lys-H+ and Ac-Phe-(Ala)10-Lys-H+, and one that we expect to be globular, Ac-Lys(H+)-Phe-(Ala)10, with the goal of identifying spectral features charact ...

2009

Collisionally-assisted spectroscopy of water from 27000 to 34000 cm-1

Oleg Boyarkine, Thomas Rizzo, Pavlo Maksyutenko, Maxim Grechko

We report here an experimental approach that enables measurement of weak transitions to a wide range of rovibrational levels of water in the energy region 27000-34200 cm-1. We have previously demonstrated the use of laser double-resonance overtone excitati ...

2008

Effects of N-terminus substitution on the structure and spectroscopy of gas-phase helices

Oleg Boyarkine, Thomas Rizzo

Because of the importance of helices in the secondary structure of proteins, we have undertaken a study of their spectroscopy, fragmentation patterns and conformations in the gas phase. In this work, we describe the effects of substitution at the N-terminu ...

2008

Spectroscopic probes of cold, gas-phase biomolecular ions: From amino acids to helical peptides

Oleg Boyarkine, Thomas Rizzo

2008

Spectroscopic signatures of gas-phase helices: Ac-Phe-(Ala)5-Lys-H+ and Ac-Phe-(Ala)10-Lys-H+

Oleg Boyarkine, Thomas Rizzo

We apply gas-phase double resonance spectroscopic techniques to two helical peptides, Ac-Phe-(Ala)5-Lys-H+ and Ac-Phe- (Ala)10-Lys-H+, using electrospray ionization combined with photofragmentation in a cold, 22-pole ion trap. Despite the large size of the ...

2007

Approaching the full set of energy levels of water

Oleg Boyarkine, Thomas Rizzo, Pavlo Maksyutenko

We report here measurements of rovibrational levels in the electronic ground state of water at the previously inaccessible energies above 26,000 cm-1. The use of laser double-resonance overtone excitation extends this limit to 34,200 cm-1, which correspond ...

2007

Conformation-specific spectroscopy and photodissociation of cold, protonated tyrosine and phenylalanine

Oleg Boyarkine, Thomas Rizzo, Sébastien Mercier, Monia Guidi, Caroline Seaiby

We present here ultraviolet and infrared spectra of protonated aromatic amino acids in a cold, 22-pole ion trap. Ultraviolet photofragmentation spectra of protonated tyrosine and phenylalanine show vibronically resolved bands corresponding to different sta ...

2007

Conformation-specific infrared and ultraviolet spectroscopy of tyrosine-based protonated dipeptides

Oleg Boyarkine, Thomas Rizzo, Monia Guidi

We present the spectroscopy and photofragmentation dynamics of two isomeric protonated dipeptides, H+AlaTyr and H+TyrAla, in a cold ion trap. By a combination of infrared-ultraviolet double resonance experiments and density functional theory calculations, ...

2007

Conformational dependence of intramolecular vibrational redistribution in methanol

Oleg Boyarkine, Thomas Rizzo, Pavlo Maksyutenko

Previous state-selected spectra of methanol in the 5ν1 OH stretch overtone region [O. V. Boyarkin, T. R. Rizzo, and D. S. Perry, J. Chem. Phys. 110 (23), 11346 (1999)] revealed structure indicating intramolecular vibrational redistribution (IVR) on three t ...

2007

Laser isotope separation method employing isotopically selective collisional relaxation

Thomas Rizzo

A method of separating isotopes from polyatomic molecules, in particular C from trifluoromethane HCF3, by applying to the polyatomic molecules in the gas phase infrared laser beams of different frequencies to produce multiphoton dissociation and reacti ...

2007

Isotopically selective collisional vibrational energy transfer in CF3H

Oleg Boyarkine, Thomas Rizzo

We investigate here the mechanism of collisionally-enhanced isotopic selectivity observed in infrared multiple photon dissociation (IRMPD) of vibrationally pre-excited CF3H by Boyarkin et al. (J. Chem. Phys. 118, 93 (2003)). For both the carbon-12 and carb ...

2007

Microsolvation effects on the excited state dynamics of protonated tryptophan

Oleg Boyarkine, Thomas Rizzo, Sébastien Mercier, Anthi Kamariotou, Ursula Röthlisberger, Ivano Tavernelli, Matteo Guglielmi, Michele Cascella

To better understand the complex photophysics of the amino acid tryptophan, which is widely used as a probe of protein structure and dynamics, we have measured electronic spectra of protonated, gas-phase tryptophan solvated with a controlled number of wate ...

2006

Efficient, highly selective laser isotope separation of carbon-13

Oleg Boyarkine, Thomas Rizzo

We recently demonstrated an original approach to highly selective laser isotope separation of carbon-13 that employs vibrational overtone pre-excitation of CF3 H together with infrared multiphoton dissociation [O.V. Boyarkin, M. Kowalczyk, T.R. Rizzo, J. C ...

Springer-Verlag2006

Electronic spectroscopy of cold, protonated tryptophan and tyrosine

Oleg Boyarkine, Thomas Rizzo, Sébastien Mercier, Anthi Kamariotou

We report here a new method to obtain electronic spectra of biomolecular ions that are produced in the gas phase by electrospray and cooled to ~10K in a 22-pole ion trap, and we demonstrate this technique by applying it to protonated tryptophan and tyrosin ...

2006

Efficient Stimulated Raman Pumping for Quantum-State Resolved Surface Reactivity Measurements

Thomas Rizzo, Rainer Beck, Plinio Maroni

We describe the use of stimulated Raman pumping in a molecular beam to perform quantum state resolved gas-surface reactivity measurements for molecules prepared in totally symmetric vibrational states. Vibrational states of homonuclear diatomics as well as ...

2006

Infrared spectroscopy of hydrated amino acids in the gas phase: protonated and lithiated valine

Oleg Boyarkine, Thomas Rizzo, Rainer Beck, Sébastien Mercier, Anthi Kamariotou, Evan Rowland Williams

We report here infrared spectra of protonated and lithiated valine with varying degrees of hydration in the gas phase and interpret them with the help of DFT calculations at the B3LYP/6-31++G** level. In both the protonated and lithiated species, our resul ...

2006

A direct measurement of the dissociation energy of water

Oleg Boyarkine, Thomas Rizzo, Pavlo Maksyutenko

We have performed a direct measurement of one of the most fundamental thermochemical values: the O-H bond energy in water. Using a triple-resonance laser excitation scheme, we excite the molecule through a series of vibrational overtone transitions to acce ...

2006

State-resolved gas-surface reactivity of methane in the symmetric C-H stretch vibration on Ni(100)

Thomas Rizzo, Rainer Beck, Plinio Maroni, Thanh Tung Dang, Marco Sacchi

The state-resolved reactivity of CH4 in its totally symmetric C-H stretch vibration (nu(1)) has been measured on a Ni(100) surface. Methane molecules were accelerated to kinetic energies of 49 and 63.5 kJ/mol in a molecular beam and vibrationally excited t ...

2005

Vibrational overtone spectroscopy of jet-cooled methanol from 5000 to 14000 cm(-1)

Oleg Boyarkine, Thomas Rizzo

Spectra of jet-cooled methanol in the overtone and combination region from 5000 to, 14000 cm(-1) have been obtained by means of infrared laser-assisted photofragment spectroscopy. Many of the observed features are assigned to combination bands of the type ...

2005

Dipole moments of HDO in highly excited vibrational states measured by Stark induced photofragment quantum beat spectroscopy

Thomas Rizzo, Patrice Theulé

We report here a measurement of electric dipole moments in highly vibrationally excited HDO molecules. We use photofragment yield detected quantum beat spectroscopy to determine electric field induced splittings of the J=1 rotational levels of HDO excited ...

2005

Page 5 sur 5