6,657 research outputs found
Moment distributiuons of clusters and molecules in the adiabatic rotor model
We present a Fortran program to compute the distribution of dipole moments of
free particles for use in analyzing molecular beams experiments that measure
moments by deflection in an inhomogeneous field. The theory is the same for
magnetic and electric dipole moments, and is based on a thermal ensemble of
classical particles that are free to rotate and that have moment vectors
aligned along a principal axis of rotation. The theory has two parameters, the
ratio of the magnetic (or electric) dipole energy to the thermal energy, and
the ratio of moments of inertia of the rotor.Comment: 3 pages with 2 figure
Nuclear pairing: basic phenomena revisited
I review the phenomena associated with pairing in nuclear physics, most
prominently the ubiquitous presence of odd-even mass differences and the
properties of the excitation spectra, very different for even-even and odd-A
nuclei. There are also significant dynamical effects of pairing, visible in the
inertias associated with nuclear rotation and large-amplitude shape
deformation.Comment: 16 pages, 10 figures, 1 table. This MS is a chapter in a review
volume on nuclear pairing. The editors of the volume are R.A. Broglia and V.
Zelevinsk
A looming revolution: Implications of self-generation for the risk exposure of retailers. ESRI WP597, September 2018
Managing the risk associated with uncertain load has always been a challenge for retailers in electricity markets. Yet
the load variability has been largely predictable in the past, especially when aggregating a large number of consumers. In
contrast, the increasing penetration of unpredictable, small-scale electricity generation by consumers, i.e. self-generation,
constitutes a new and yet greater volume risk. Using value-at-risk metrics and Monte Carlo simulations based on German
historical loads and prices, the contribution of decentralized solar PV self-generation to retailers’ load and revenue risks is
assessed. This analysis has implications for the consumers’ welfare and the overall efficiency of electricity markets
Determinants of power spreads in electricity futures markets: A multinational analysis. ESRI WP580, December 2017
The growth in variable renewable energy (vRES) and the need for flexibility in power
systems go hand in hand. We study how vRES and other factors, namely the price of substitute
fuels, power price volatility, structural breaks, and seasonality impact the hedgeable power
spreads (profit margins) of the main dispatchable flexibility providers in the current power
systems - gas and coal power plants. We particularly focus on power spreads that are hedgeable
in futures markets in three European electricity markets (Germany, UK, Nordic) over the time
period 2009-2016. We find that market participants who use power spreads need to pay
attention to the fundamental supply and demand changes in the underlying markets (electricity,
CO2, and coal/gas). Specifically, we show that the total vRES capacity installed during 2009-2016
is associated with a drop of 3-22% in hedgeable profit margins of coal and especially gas power
generators. While this shows that the expansion of vRES has a significant negative effect on the
hedgeable profitability of dispatchable, flexible power generators, it also suggests that the
overall decline in power spreads is further driven by the price dynamics in the CO2 and fuel
markets during the sample period. We also find significant persistence (and asymmetric effects)
in the power spreads volatility using a univariate TGARCH model
Optical response of small carbon clusters
We apply the time-dependent local density approximation (TDLDA) to calculate
dipole excitations in small carbon clusters. A strong low-frequency mode is
found which agrees well with observation for clusters C_n with n in the range
7-15. The size dependence of the mode may be understood simply as the classical
resonance of electrons in a conducting needle. For a ring geometry, the lowest
collective mode occurs at about twice the frequency of the collective mode in
the linear chain, and this may also be understood in simple terms.Comment: 19 pages, Latex(Revtex), and 7 figures Postscript; to be published in
Zeit. Phys. D; contact is [email protected]
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