Slit width

Slit width is one of the important variables in spectrophotometry. Slit width, determines the resolution and the measured extinction coefficients of the absorption bands. The possibility of the lack of resolution of absorption 

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When dispersing elements are used, the resolution of the speetrometer is detennined by the entranee slit widtir, the exit slit width, the foeal length and the dispersing element itself Resolving power is defined as... 

A7 Ethane/methane selectivity calculated from grand canonical Monte Carlo simulations of mixtures in slit IS at a temperature of 296 K. The selectivity is defined as the ratio of the mole fractions in the pore to the ratio of mole fractions in the bulk. H is the slit width defined in terms of the methane collision diameter (Tch,- (Figure awn from Crackncll R F, D Nicholson and N Quirke 1994. A Grand Canonical Monte Carlo Study ofLennard-s Mixtures in Slit Pores 2 Mixtures of Two-Centre Ethane with Methane. Molecular Simulation 13 161-175.)... 

Data for the several flame methods assume an acetylene-nitrous oxide flame residing on a 5- or 10-cm slot burner. The sample is nebulized into a spray chamber placed immediately ahead of the burner. Detection limits are quite dependent on instrument and operating variables, particularly the detector, the fuel and oxidant gases, the slit width, and the method used for background correction and data smoothing. 

Effect of the monochromator s slit width on noise and resolution for the ultraviolet absorption spectrum of benzene. The slit width increases from spectrum (a) to spectrum (d) with effective bandpasses of 0.25 nm, 1.0 nm, 2.0 nm, and 4.0 nm. 

The emission spectrum from a hollow cathode lamp includes, besides emission lines for the analyte, additional emission lines for impurities present in the metallic cathode and the filler gas. These additional lines serve as a potential source of stray radiation that may lead to an instrumental deviation from Beer s law. Normally the monochromator s slit width is set as wide as possible, improving the throughput of radiation, while being narrow enough to eliminate this source of stray radiation. 

M HNO3. The concentration of Cu and Zn in the diluted supernatant is determined by atomic absorption spectroscopy using an air-acetylene flame and external standards. Copper is analyzed at a wavelength of 324.8 nm with a slit width of 0.5 nm, and zinc is analyzed at 213.9 nm with a slit width of 1.0 nm. Background correction is used for zinc. Results are reported as micrograms of Cu or Zn per gram of FFDT. 

Atomic emission is used for the analysis of the same types of samples that may be analyzed by atomic absorption. The development of a quantitative atomic emission method requires several considerations, including choosing a source for atomization and excitation, selecting a wavelength and slit width, preparing the sample for analysis, minimizing spectral and chemical interferences, and selecting a method of standardization. 

This experiment describes a fractional factorial design used to examine the effects of flame height, flame stoichiometry, acetic acid, lamp current, wavelength, and slit width on the flame atomic absorbance obtained using a solution of 2.00-ppm Ag+. 

In XPS the photoelectrons are retarded to a constant energy, called the pass energy, as they approach the entrance slit. If this were not done, Eq. (2.5) shows that to achieve an absolute resolution of 1 eV at the maximum kinetic energy of approximately 1500 eV (using A1 Ka radiation), and with a slit width of 2 mm, would require an analyzer with an average radius of about 300 cm, which is impracticable. Pass energies are selected in the range 20-100 eV for XPS, which enables the analyzer to be built with a radius of 10-15 cm. 

For this technique, the upper plate has a mobile phase inlet channel on one edge and a slit at the opposite edge for directing the mobile phase toward the next plate (33). The slit (width approx. 0.1 mm) can be produced by cutting the layers with a sharp blade this enables easy passage of mobile phase and separated compounds without any mixing. The cushion of the OPLC instrument is applied to the uppermost layer only, and each plate presses on to the sorbent layer below. 

When reporting spectrophotometric measurements, details should be given of the concentration used, the solvent employed, the make and model of the instrument, as well as the slit widths employed, together with any other pertinent information. 

The experimental technique is simple. The cell containing the solution to be titrated is placed in the light path of a spectrophotometer, a wavelength appropriate to the particular titration is selected, and the absorption is adjusted to some convenient value by means of the sensitivity and slit-width controls. A measured volume of the titrant is added to the stirred solution, and the absorbance is read again. This is repeated at several points before the end point and several more points after the end point. The latter is found graphically. 

Procedure. Charge the titration cell (Fig. 17.24) with 10.00 mL of the copper ion solution, 20 mL of the acetate buffer (pH = 2.2), and about 120mL of water. Position the cell in the spectrophotometer and set the wavelength scale at 745 nm. Adjust the slit width so that the reading on the absorbance scale is zero. Stir the solution and titrate with the standard EDTA record the absorbance every 0.50 mL until the value is about 0.20 and subsequently every 0.20 mL. Continue the titration until about 1.0 mL after the end point the latter occurs when the absorbance readings become fairly constant. Plot absorbance against mL of titrant added the intersection of the two straight lines (see Fig. 17.23 C) is the end point. 

Fig. 11. Change of the fluorescence spectra of polyfpropynoic acid)s as a result of transfer from solution [(1) PPAL, (2) PPASJ to the solid phase [(3) PPAL, (4) PPASJ. Concentration of aqueous solutions 10 4 mol/1. The fluorescence spectra of the samples in solid phase were taken from powdered polymers placed between two quartz plates. Slit width 0.2 mm sensitivity 3,0 excitation = 365 nm. / = intensity...

Element Analyt- ical Line Wavelength, A Crystal Slit Width, in. Path Type of Detector Detector Path Length, cm Detector Window"... 

Figure 9. Predicted resolving power for CMOS equipped with the gratings described in Table 1 and slit width 0,5 arcsec. Those prefixed by X are hypothetical immersed gratings with prism vertex angle, (j>, given in the Table 1. The dots mark the nominal blaze condition. The box marks the requirements for measuring the velocity dispersion of dSph galaxies using the Calcium triplet.

Figure 8.4 illustrates pressure-driven flow between flat plates. The downstream direction is The cross-flow direction is y, with y = 0 at the centerline and y = Y at the walls so that the channel height is 2Y. Suppose the slit width (x-direction) is very large so that sidewall effects are negligible. The velocity profile for a laminar, Newtonian fluid of constant viscosity is... 

Which is better for isothermal chemical reactions, pressure driven flow or drag flow between flat plates Assume laminar flow with first-order chemical reaction and compare systems with the same values for the slit width (2Y=H), length, mean velocity, and reaction rate constant. 

Mixer channel width, depth slit width 40 pm 300 pm 60 pm Tube length Up to 150 cm... 

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