The normal procedure for numerical simulation of exponentially correlated colored noise is superseded by the novel algorithm presented here. A differential algorithm is replaced by an integral algorithm which is faster, more accurate, and permits the use of longer step sizes.

Articles you may be interested inCentroid molecular dynamics approach to the transport properties of liquid para-hydrogen over the wide temperature range Shunting arc plasma generation over a wide range of ambient pressure and ion extraction Rev. Sci. Instrum. 73, 860 (2002); 10.1063/1.1427667Reduced state relationship for limiting electrical conductances of aqueous ions over wide ranges of temperature and pressure System employing laser heating for the measurement of hightemperature properties of materials over a wide pressure range Rev. Sci. Instrum. 48, 632 (1977);We have investigated in drift tube mass spectrometers the identity and the transport properties of ions formed in CO, gas at pressures ranging from 10-4 to 762 torr. Under bombardment by low energy (20-100 eV) electrons in the ion source, the primary positive ion is predominantly coj, with traces of C+, 0+, and CO'. The predominant ion becomes oj at pressures above 100 J.L (0.1 torr), and clustering of CO, molecules to the 0; occurs even at pressures below I torr. Break-up of the clusters also occurs, the ion identity changing many times in the drift region. The zero-field reduced mobility of the oj ·(CO,). charge carrier is a function of pressure, and varies from (1.30±0.03) cm'/V·sec at 0.2 torr to (I.l8±0.03) cm 2 /V·sec at I torr. The sole negative ion produced directly by the electron bombardment is 0-, which clusters to form the stable ion CO). whose reduced mobility is (1.27±0.06) cm'/V·sec for EIN ~60 Td at all pressures below I torr. At much higher pressures and under somewhat different conditions (above 30 torr and using beta source ionization), ions in CO, are observed to form multiple clusters, the population distribution among the clusters being strongly dependent on gas temperature. The zero-field reduced mobility of the charge carrier is largely independent of the identity of the core ion, and varies with pressure from roughly 1.2 cm' IV·sec at 35 torr to about 1.0 cm'/V.sec at 762 torr. drift energy is small compared to the thermal energy, Ko is independent of E/N and has a magnitude called the zero-field mobility. Lasers typically operate at E/N well within this low-field region.

We have measured, with a drift tube mass spectrometer, the mobilities and longitudinal diffusion coefficients of K+ ions in nitrogen and carbon monoxide at 300°K. The measurements were made over a range of E/N extending from thermal values up to 636 × 10−17 V·cm2. Here E is the drift field intensity and N is the gas number density. The zero-field reduced mobilities of K+ ions in N2 and CO were determined to be (2.54 ± 0.05) and (2.30 ± 0.04) cm2/V · sec, respectively. The low-field diffusion coefficients are in excellent agreement with the values calculated by the Einstein equation from the experimental zero-field mobilities. The experimental diffusion coefficients are compared with the predictions of an equation developed by Wannier on the assumption that the ion-molecule interaction consists of only the attractive polarization force, of which a constant mean free time between collisions is a consequence. Comparison is also made with a modified version of this equation which contains the ionic drift velocity rather than the mean free time. The agreement between the experimental data and the modified Wannier equation is very close up to average ionic energies of about 0.6 eV. We also observed clustering of single molecules of CO2, NO, CO, N2, O2, Ar, D2, Ne, and He to K+ ions when the drift tube was filled successively with the indicated gases. At room temperature, clustering is likely to be of importance in studies of the transport properties of K+ ions in all of these gases except D2, Ne, and He.

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