High-resolution spectroscopy of He2+_2^+ using Rydberg-series extrapolation and Zeeman-decelerated supersonic beams of metastable He2_2

Recently, high-resolution spectroscopy of slow beams of metastable helium molecules (He$_2^*$) generated by multistage Zeeman deceleration was used in combination with Rydberg-series extrapolation techniques to obtain the lowest rotational interval in the molecular helium ion at a precision of 18 MHz [Jansen et al. Phys. Rev. Lett. 115 (13) (2015) 133202], limited by the temporal width of the Fourier-transform-limited laser pulses used to record the spectra. We present here an extension of these measurements in which we have (1) measured higher rotational intervals of He${_2}^+$, (2) replaced the pulsed UV laser by a cw UV laser and improved the resolution of the spectra by a factor of more than five, and (3) studied $M_J$ redistribution processes in regions of low magnetic fields of the Zeeman decelerator and shown how these processes can be exploited to assign transitions originating from specific spin-rotational levels ($N^{\prime\prime},J^{\prime\prime}$) of He$_2^*$.Comment: 28 pages, 8 figure

Comovement in international equity markets: A sectoral view

We investigate shifts in correlation patterns among international equity returns at the market level as well as the industry level. We develop a novel bivariate GARCH model for equity returns with a smoothly time- varying correlation and then derive a Lagrange Multiplier statistic to test the constant-correlation hypothesis directly. Applying the test to weekly data from Germany, Japan, the UK and the US in the period 1980- 2000, we find that correlations among the German, UK and US stock markets have doubled, whereas Japanese correlations have remained the same. Both dates of change and speeds of adjustment vary widely across countries and sectors.stock market linkages; financial integration; smooth transition

Precision measurement of the rotational energy-level structure of the three-electron molecule He2+_2^+

The term values of all rotational levels of the $^4$He{_2}^+\,X^+\,^2\Sigma_u^+\,(\nu^+=0) ground vibronic state with rotational quantum number $N^+\le 19$ have been determined with an accuracy of 8 x 10$^{-4}$ cm$^{-1}$ ($\sim{25}$ MHz) by MQDT-assisted Rydberg spectroscopy of metastable He$_2^*$. Comparison of these term values with term values recently calculated ab initio by Tung et al. [J. Chem. Phys. 136, 104309 (2012)] reveal discrepancies that rapidly increase with increasing rotational quantum number and reach values of 0.07 cm$^{-1}$ ($\sim{2.1}$ GHz) at $N^+=19$.Comment: 11 pages, 6 figure

The multiple sources of autonomy as a start-up motive

Autonomy is a primary motive for a large majority of small business starters. However, as an explanation of why people want their own (autonomous) business it is largely circular. In this paper, we focus on an explanation of the autonomy motive itself. We provide a theoretical and empirical exposition of autonomy as a startup motive. Specifically, it is questioned why small business starters want autonomy. A distinction is made between proximal and distal reasons for wanting autonomy. Our framework is confirmed studying a sample of 167 nascent entrepreneurs motivated by autonomy. The findings suggest that beneath the surface of small business starters striving for autonomy, they differ in their relative emphasis on the underlying sources of the autonomy motive.