Ultrafast Intramolecular Charge Transfer of Formyl Perylene Observed Using Femtosecond Transient Absorption Spectroscopy

The excited-state photophysics of formylperylene (FPe) have been investigated in a series of nonpolar, polar aprotic, and polar protic solvents. A variety of experimental and theoretical methods were employed including femtosecond transient absorption (fs-TA) spectroscopy with 130 fs temporal resolution. We report that the ultrafast intramolecular charge transfer from the perylene unit to the formyl (CHO) group can be facilitated drastically by hydrogen-bonding interactions between the carbonyl group oxygen of FPe and hydrogen-donating solvents in the electronically excited state. The excited-state absorption of FPe in methanol (MeOH) is close to the reported perylene radical cation produced by bimolecular quenching by an electron acceptor. This is a strong indication for a substantial charge transfer in the S1 state in protic solvents. The larger increase of the dipole moment change in the protic solvents than that in aprotic ones strongly supports this observation. Relaxation mechanisms including vibrational cooling and solvation coupled to the charge-transfer state are also discussed

An Investigation into the 1999 Collapse of the Brazilian Real

This study argues that the political considerations were an important factor behind the crisis of the Brazilian real in January 1999. The divided coalition government and a president facing impending elections eschewed the correction of external misalignments and the fiscal austerity at a time when the markets were already excited by the 1997-98 East Asian and 1998 Russian financial crises. The hypothesis is established after confirming the vulnerability of Brazilian economy to currency crisis through Masson's model of multiple equilibrium and then it is tested by running a maximum likelihood logit regression.

Majorization and Measures of Classical Polarization in Three Dimensions

There has been much discussion in the literature about rival measures of classical polarization in three dimensions. We gather and compare the various proposed measures of polarization, creating a geometric representation of the polarization state space in the process. We use majorization, previously used in quantum information, as a criterion to establish a partial ordering on the polarization state space. Using this criterion and other considerations, the most useful polarization measure in three dimensions is found to be one dependent on the Bloch vector decomposition of the polarization matrix.Comment: 8 page

Political Instability and the August 1998 Ruble Crisis

The main objective of this study is to highlight the importance of political instability, defined as frequent changes in and of government, in undermining the Russian exchange rate based stabilization program of the 1990s. The empirical evidence supports the significance of political instability along with economic fundamentals in determining Russian real effective exchange rate and exchange market pressure, used as a proxy to the crisis.Currency crises, political instability

Practical Provably Secure Multi-node Communication

We present a practical and provably-secure multimode communication scheme in the presence of a passive eavesdropper. The scheme is based on a random scheduling approach that hides the identity of the transmitter from the eavesdropper. This random scheduling leads to ambiguity at the eavesdropper with regard to the origin of the transmitted frame. We present the details of the technique and analyze it to quantify the secrecy-fairness-overhead trade-off. Implementation of the scheme over Crossbow Telosb motes, equipped with CC2420 radio chips, shows that the scheme can achieve significant secrecy gain with vanishing outage probability. In addition, it has significant overhead advantage over direct extensions to two-nodes schemes. The technique also has the advantage of allowing inactive nodes to leverage sleep mode to further save energy.Comment: Proceedings of the IEEE International Conference on Computing, Networking and Communications (ICNC 2014

Monetary Targeting in Pakistan: A Skeptical Note

The objective of this study is to evaluate monetary targeting strategy in Pakistan by testing the Quantity Theory of Money and the income velocity of money stated by Monetarists and the endogenous money hypothesis postulated by the Post Keynesians. Our tests on the Pakistani data covering about thirty years reveal that the quantity theory is an inadequate explanation of inflation, income velocity of money is unstable, and money is endogenous. These results suggest rethinking on monetary targeting strategy in Pakistan.Monetary Targeting, QTM, Income Velocity of Money, Endogenous Money