1,413 research outputs found

    Corrections to the Born-oppenheimer Approximation, Part II

    Get PDF
    Adiabatic corrections to long-range Born- Oppenheimer potential

    The Cusp Conditions for Molecular Wave Functions

    Get PDF
    Cusp conditions to describe behavior of wave function at singularities of Coulomb potential corresponding to coalescence of two or more particles - diatomic molecule

    Kinematic Orbits and the Structure of the Internal Space for Systems of Five or More Bodies

    Get PDF
    The internal space for a molecule, atom, or other n-body system can be conveniently parameterised by 3n-9 kinematic angles and three kinematic invariants. For a fixed set of kinematic invariants, the kinematic angles parameterise a subspace, called a kinematic orbit, of the n-body internal space. Building on an earlier analysis of the three- and four-body problems, we derive the form of these kinematic orbits (that is, their topology) for the general n-body problem. The case n=5 is studied in detail, along with the previously studied cases n=3,4.Comment: 38 pages, submitted to J. Phys.

    Aging is associated with an earlier arrival of reflected waves without a distal shift in reflection sites

    Get PDF
    Background-Despite pronounced increases in central pulse wave velocity (PWV) with aging, reflected wave transit time (RWTT), traditionally defined as the timing of the inflection point (T-INF) in the central pressure waveform, does not appreciably decrease, leading to the controversial proposition of a "distal-shift" of reflection sites. T-INF, however, is exceptionally prone to measurement error and is also affected by ejection pattern and not only by wave reflection. We assessed whether RWTT, assessed by advanced pressure-flow analysis, demonstrates the expected decline with aging. Methods and Results-We studied a sample of unselected adults without cardiovascular disease (n=48; median age 48 years) and a clinical population of older adults with suspected/established cardiovascular disease (n=164; 61 years). We measured central pressure and flow with carotid tonometry and phase-contrast MRI, respectively. We assessed RWTT using wave-separation analysis (RWTTWSA) and partially distributed tube-load (TL) modeling (RWTTTL). Consistent with previous reports, T-INF did not appreciably decrease with age despite pronounced increases in PWV in both populations. However, aging was associated with pronounced decreases in RWTTWSA (general population -15.0 ms/decade, P<0.001; clinical population -9.07 ms/decade, P=0.003) and RWTTTL (general -15.8 ms/decade, P<0.001; clinical -11.8 ms/decade, P<0.001). There was no evidence of an increased effective reflecting distance by either method. TINF was shown to reliably represent RWTT only under highly unrealistic assumptions about input impedance. Conclusions-RWTT declines with age in parallel with increased PWV, with earlier effects of wave reflections and without a distal shift in reflecting sites. These findings have important implications for our understanding of the role of wave reflections with aging

    An intelligent robotic aid system for human services

    Get PDF
    The long term goal of our research at the Intelligent Robotic Laboratory at Vanderbilt University is to develop advanced intelligent robotic aid systems for human services. As a first step toward our goal, the current thrusts of our R&D are centered on the development of an intelligent robotic aid called the ISAC (Intelligent Soft Arm Control). In this paper, we describe the overall system architecture and current activities in intelligent control, adaptive/interactive control and task learning

    Corn Silage Performance, 2004; Cache County, Utah

    Get PDF

    Silage Corn Performance, 2003; Cache and Davis Counties, Utah

    Get PDF

    Boundary Conditions on Internal Three-Body Wave Functions

    Get PDF
    For a three-body system, a quantum wave function Ψmℓ\Psi^\ell_m with definite ℓ\ell and mm quantum numbers may be expressed in terms of an internal wave function χkℓ\chi^\ell_k which is a function of three internal coordinates. This article provides necessary and sufficient constraints on χkℓ\chi^\ell_k to ensure that the external wave function Ψmℓ\Psi^\ell_m is analytic. These constraints effectively amount to boundary conditions on χkℓ\chi^\ell_k and its derivatives at the boundary of the internal space. Such conditions find similarities in the (planar) two-body problem where the wave function (to lowest order) has the form r∣m∣r^{|m|} at the origin. We expect the boundary conditions to prove useful for constructing singularity free three-body basis sets for the case of nonvanishing angular momentum.Comment: 41 pages, submitted to Phys. Rev.
    • …
    corecore