ExoMol molecular line lists - XVI: The rotation-vibration spectrum of hot H2_2S

This work presents the AYT2 line list: a comprehensive list of 114 million $^{1}$H$_2$$^{32}$S vibration-rotation transitions computed using an empirically-adjusted potential energy surface and an {\it ab initio} dipole moment surface. The line list gives complete coverage up to 11000 \cm\ (wavelengths longer than 0.91 $\mu$m) for temperatures up to 2000 K. Room temperature spectra can be simulated up to 20000 \cm\ (0.5 $\mu$m) but the predictions at visible wavelengths are less reliable. AYT2 is made available in electronic form as supplementary data to this article and at \url{www.exomol.com}.Comment: 12 pages, 10 figures, 10 table

Analogy Between Linear Optical Systems and Linear Two-Port Electrical Networks

Attention is called to the analogy between linear optical systems and linear two-port electrical networks. For both, the transformation of a pair of oscillating quantities between input and output is of interest. The mapping of polarization by an optical system and of impedance (admittance) by a two-port network is described by a bilinear transformation. Therefore for each transfer property of a system of one type, there is a similar property for the system of the other type. Two-port electrical networks are synthesized whose impedance-(or admittance-) mapping properties are the same as the polarization-mapping properties of a given optical system. The opposite problem of finding the optical analogs of two-port networks is also considered. Besides unifying the methods of handling these two different kinds of systems, the analogy appears fruitful if used reciprocally to simulate electrical networks by optical systems, and vice versa. Linear mechanoacoustic systems have optical analogs besides their well-known electrical analogs

Analogy Between Linear Optical Systems and Linear Two-Port Electrical Networks

Attention is called to the analogy between linear optical systems and linear two-port electrical networks. For both, the transformation of a pair of oscillating quantities between input and output is of interest. The mapping of polarization by an optical system and of impedance (admittance) by a two-port network is described by a bilinear transformation. Therefore for each transfer property of a system of one type, there is a similar property for the system of the other type. Two-port electrical networks are synthesized whose impedance-(or admittance-) mapping properties are the same as the polarization-mapping properties of a given optical system. The opposite problem of finding the optical analogs of two-port networks is also considered. Besides unifying the methods of handling these two different kinds of systems, the analogy appears fruitful if used reciprocally to simulate electrical networks by optical systems, and vice versa. Linear mechanoacoustic systems have optical analogs besides their well-known electrical analogs

Loci of Invariant-Azimuth and Invariant-Ellipticity Polarization States of an Optical System

The loci of polarization states for which either the ellipticity alone or the azimuth alone remains invariant upon passing through an optical system are introduced. The cartesian equations of these two loci are derived in the complex plane in which the polarization states are represented. The equations are quartic and are conveniently expressed in terms of the elements of the Jones. matrix of the optical system. As an exple the loci are determined for a system composed of a π/4 rotator followed by a quarter-wave retarder

Ellipsometer nulling: convergence and speed

The process of nulling in ellipsometry is studied by a graphical presentation using the trajectories of two significant polarization states in the complex plane, XPC and XSA. These states are determined by (1) the polarizer and compensator (XPC) and (2) the specimen and the analyzer (XSA) in the polarizer-compensator-specimen-analyzer ellipsometer arrangement. As the azimuth angles of the ellipsometer elements are varied, XPC and XSA move closer to one another in a stepwise fashion until they coincide when a null is reached. Thus, at null, the polarization states are matched, and XPC = XSA. For an isotropic reflector, the trajectory of XSA is a straight line, which simplifies the development of a criterion for achieving the most rapid nulling for two nulling procedures

Ellipsometer nulling: convergence and speed

The process of nulling in ellipsometry is studied by a graphical presentation using the trajectories of two significant polarization states in the complex plane, XPC and XSA. These states are determined by (1) the polarizer and compensator (XPC) and (2) the specimen and the analyzer (XSA) in the polarizer-compensator-specimen-analyzer ellipsometer arrangement. As the azimuth angles of the ellipsometer elements are varied, XPC and XSA move closer to one another in a stepwise fashion until they coincide when a null is reached. Thus, at null, the polarization states are matched, and XPC = XSA. For an isotropic reflector, the trajectory of XSA is a straight line, which simplifies the development of a criterion for achieving the most rapid nulling for two nulling procedures

Relativistic Operator Description of Photon Polarization

We present an operator approach to the description of photon polarization, based on Wigner's concept of elementary relativistic systems. The theory of unitary representations of the Poincare group, and of parity, are exploited to construct spinlike operators acting on the polarization states of a photon at each fixed energy momentum. The nontrivial topological features of these representations relevant for massless particles, and the departures from the treatment of massive finite spin representations, are highlighted and addressed.Comment: Revtex 9 page