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The energy gain in specific rational levels of vibrationally excited H(sub 2)O(010) which resulted from collisions with highly vibrationally excited pyrazine in a low-pressure, 298 K environment are investigated using high-resolution transient infrared absorption spectroscopy of water at Lambda approximately equal to 2.7 mm. The molecular properties of the energy acceptor that influence the relaxation of highly virbationally excited molecules are explored.

Rotational state-resolved differential cross sections (DCS) for spin-multiplet-changing collisions of NO(X[SUP2]Π[SUB1/2]→X[SUP2[Π[SUB3/2]) with Ar are presented and compared to results from previous experimental and theoretical studies performed on the NO/Ar system. A crossed molecular beam apparatus coupled with velocity-mapped ion imaging was used to measure complete (&theta=0°-180°) DCS for scattering of NO(X[SUP2]Π1/2],j=0.5) into NO(X[SUP2]Π3/2,j′) rotational states ranging from j′ = 1.5 to j′ = 12.5. Scattered products were detected by state-selective ionization using (1+1′) resonance-enhanced multiphoton ionization via the A[SUP2]Σ[SUP+] state. State-to-state DCS were extracted in the center-of-mass frame of reference for energy transfer at a center-of-mass collision energy of ∼530 cm[SUP-1]. Studies performed using horizontally and vertically polarized excitation laser beams yielded DCS which were remarkably similar, indicating that state-to-state scattering for this system is insensitive to probe beam polarization. Experimentally determined angular scattering distributions show primarily forward scattering for low-energy rotational states (j≤7.5), with side- and back-scattering increasing with product angular momentum. The scattering results are compared and contrasted to results from earlier experimental investigations and to theoretical results from quantum close-coupling calculations based on ab initio coupled cluster CCSD(T) potential energy surfaces. [ABSTRACT FROM AUTHOR]

Investigates the influence of long-range attractive forces on collisional energy loss from highly vibrationally excited molecules. State-resolved studies of energy transfer from highly vibrationally excited pyridine to water in a low pressure environment; Nascent distribution of rotationally excited water.

Studies the energy threshold for large Delta E collisional relaxation of highly vibrationally excited pyrazine (E[sub vib]=31 000-41 000 cm[sup -1] by carbon dioxide. Energy-dependent transient absorption measurements; Energy-dependent nascent velocity distributions of CO[sub 2]; Energy-dependent nascent distributions of CO[sub 2] high J states.

The energy gain in the rotational and translational degrees of freedom of H2O(000) following collisions with highly vibrational excited pyrazine is studied. Results show that three factors determine the overall quenching efficiency of an excited molecule. These are the magnitude of the energy transferred into a specific bath state in a successful collision, probability that this event occurs and the number of acceptor states where energy can be transferred.

We report the cooling of nitric oxide using a single collision between an argon atom and a molecule of NO. We have produced significant numbers (10[sup8] to 10[sup9] molecules per cubic centimeter per quantum state) of translationally cold NO molecules in a specific quantum state with an upper-limit root mean square laboratory velocity of 15 plus or minus 1 meters per second, corresponding to a 406 plus or minus 23 millikelvin upper limit of temperature, in a crossed molecular beam apparatus. The technique, which relies on a kinematic collapse of the velocity distributions of the molecular beams for the scattering events that produce cold molecules, is general and independent of the energy of the colliding partner. [ABSTRACT FROM AUTHOR]

Presents a correction to the article on benzenes entitled 'Methylation Effects in State Resolved Quenching of Highly Vibrationally Exited Azabenzenes (Esub[vib]~38500 cm sup[-1]). I. Collisions With Water,' published in the 'Journal of Chemical Physics.'

To investigate the role of molecular structure in collisions that quench highly vibrationally excited molecules, we have performed state resolved transient infrared absorption studies of energy gain in a number of rotational levels of H[sub 2]O(000) resulting from collisions of water with vibrationally excited 2-methylpyridine (2-picoline) and 2,6-dimethylpyridine (2,6-lutidine) in a low-pressure gas-phase environment at 298 K. Vibrationally excited methylpyridines were prepared with ∼38 500 cm-1 of internal energy using 266 nm ultraviolet excitation to an S[sub 1] electronic state followed by rapid radiationless decay to the S[sub 0] electronic state. Collisions that populate rotationally excited states of H[sub 2]O(000) were investigated with infrared absorption by monitoring the appearance of individual rotational states of H[sub 2]O(000) with energies between 1000 and 2000 cm-1. Rotational state distributions for recoiling water molecules were characterized by Boltzmann temperatures of T[sub rot]=590±90 K for quenching of hot picoline and T[sub rot]=490±80 K for lutidine quenching. Doppler-broadened transient absorption line profiles show that the scattered H[sub 2]O(000) molecules have laboratory-frame translational energy distributions corresponding to T[sub trans]approx. 600 K for deactivation of picoline and T[sub trans]approx. 590 K for lutidine. Energy transfer rate constant measurements indicate that rotational excitation of H[sub 2]O(000) with E[sub vib]>1000 cm[sup -1] occurs for one in 31 picoline/water collisions and one in 17 lutidine/water collisions. Comparison with earlier quenching studies on pyrazine [M. Fraelich, M. S. Elioff, and A. S. Mullin, J. Phys. Chem. 102, 9761 (1998)] and pyridine [M. S. Elioff, M. Fraelich, R. L. Sansom, and A. S. Mullin, J. Chem. Phys. 111, 3517 (1999)] indicate that, for the same initial internal energy in the hot donor, the extent of rotational excitation in water is diminished as the num... [ABSTRACT FROM AUTHOR]

Detection of heavy metal ions in water is important for environmental sustainability and food safety. Current fluorescent sensors interact with metal ions directly through chelation or chemical reactions. Those sensors are expensive to produce and often can detect only one ion at a time. Here we report a fluorescent turn-on sensor that can detect three group IIB metal ions and Pb 2+ ions through label-free polypeptides in water. In our sensor-polypeptide mixture, Zn 2+ , Cd 2+ , Hg 2+ , and Pb 2+ ions induce helix formation and inter-chain aggregation in poly-L-α-glutamic acid (PGA). The acridinium-based sensor molecules incorporate into the polypeptides and emit strongly with characteristic color for each group IIB ion under UV lamp. By adjusting the size of polypeptides or the length of the side chain carboxyl groups, we can selectively turn off or turn on the sensor emission for Hg 2+ ions., (Copyright © 2018 Elsevier B.V. All rights reserved.)