We present the implementation of a new crossed-molecular beam, velocity-map ion-imaging apparatus, optimized for collisions of electronically excited molecules. We have applied this apparatus to rotational energy transfer in NO(A(2)Σ(+), v = 0, N = 0, j = 0.5) + Ar collisions, at an average energy of 525 cm(-1). We report differential cross sections for scattering into NO(A(2)Σ(+), v = 0, N' = ...

Photoinitiated unimolecular decomposition rate constants of rotationally excited NO2 molecules have been measured near dissociation threshold (D0) by employing a double resonance technique. Rotational selectivity has been achieved by using narrow-linewidth ~0.015 cm! infrared excitation to prepare specific rotational levels (N851,3,...,15, Ka850) of the ~1,0,1! vibrational level. The picosecond...

A novel experimental technique was used to quantify the motion of E. coli to varying serine concentrations and gradients so as to capture the spatial and temporal variation of the chemotactic response. The average run speed and the cell diffusivity are found to be dependent on the serine concentration. The measured diffusivities were in the range of 1.2-2.5 x 10 (-10) m(2) s(-1). The study reve...

Computational methods available for the calculation of relative and absolute binding affinities (free energy simulations, continuum electrostatics, linear interaction energy approximations, and empirical solvation models) are reviewed together with recent applications to biological systems. The decomposability of the binding free energy into physically meaningful components is examined and resu...

We report six-dimensional (6D) potential energy surface (PES) and rovibrational scattering calculations for the CN-H2 collision system. The PES was computed using the high-level ab initio spin-restricted coupled-cluster with single, double, and perturbative triple excitations-F12B method and fitted to an analytic function using an invariant polynomial method in 6D. Quantum close-coupling calcul...

The rotational spectrum of protonated carbon disulfide, HSCS(+), has been detected in the centimeter-wave band in a molecular beam by Fourier transform microwave spectroscopy. Rotational and centrifugal distortion constants have been determined from ten transitions in the K(a)=0 ladder of the normal isotopic species, HS(13)CS(+), and DSCS(+). The present assignment agrees well with high-level c...

The new compound H3PAgI has been synthesized in the gas phase by means of the reaction of laser-ablated silver metal with a pulse of gas consisting of a dilute mixture of ICF3 and PH3 in argon. Ground-state rotational spectra were detected and assigned for the two isotopologues H3P(107)AgI and H3P(109)AgI in their natural abundance by means of a chirped-pulse, Fourier-transform, microwave spect...

Molecular endofullerenes are supramolecular systems consisting of fullerene cages encapsulating small molecules. Although most early examples consist of encapsulated metal clusters, recently developed synthetic routes have provided endofullerenes with non-metallic guest molecules in high purity and macroscopic quantities. The encapsulated light molecule behaves as a confined quantum rotor, disp...

Ab initio potential energy and dipole moment surfaces are computed for sulfur trioxide (SO3) at the CCSD(T)-F12b level of theory and appropriate triple-zeta basis sets. These surfaces are fitted and used, with a slight correction for the equilibrium S–O distance, to compute pure rotational and rotation-vibraton spectra of SO3 using the variational nuclear motion program TROVE. The calculations ...