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Jos A.C. Broekaert. Analytic Atomic Spectroscopy with Flames and Plasmas (Wiley-VCH,2001)(ISBN 3527301461)(375s)_Ch_.pdf |
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Size 2.2Mb Date Dec 22, 2004 |
Typesetting Asco Typesetters, Hong Kong Printing betz-druck gmbH, D-64291 Darmstadt Bookbinding Wilhelm Osswald & Co., 67433 Neustadt ISBN 3-527-30146-1...
Index counter electrode 124, 127 coupling 7 crater diameter 251 crater pro®le 145 rf discharge 146 crater 133, 246 depth 134 diameter 133 critical concentration ratio 224 cross-contamination 130 cross-¯ow nebulizer 227 cross section 8, 297 crossed polarizers 183 crossed-dispersion 206 crossed-dispersion mode 59 cryocooling 285 cryopump 84 CsCl 213 Cu a Zn alloy 268 current-carrying plasma 235 current modulated 156 current ± voltage characteristic 137, 141, 142 cuvette 165, 173 Czerny ± Turner monochromator 199 D2 -lamp technique 178 Daly ± Multiplier 277 dark current 45, 65 data acquisition and treatment 84 dc arc 10 stabilized 212 dc arc spectrography 213 dc discharge 124 dc glow discharge with a ¯at cathode 244 dead time 81 Debye length 83 decay function 109 degassing 285 degeneracy 196 degree of dissociation 160 degree of ionization 20, 257 densitometer 62, 63, 254 departure from LTE 226 depression 164 depth-pro®le 248, 287 depth-pro®le analysis 246 depth-pro®ling analysis of steel 287 depth resolution 287 desolvate 104 desolvation 267 membrane 103 detecter noise 148 detection phase-sensitive 294 detection limit 182, 184, 201, 218, 223, 235, 237, 238, 243, 263, 277, 295, 296 ¯ame AAS 163, 169 furnace AAS 169 detection of the halogen 243 detector spectral response 13 determination sequential 202 simultaneous 202 deuterium lamp technique 177 diatomic molecule 26 diraction angle 207 diraction order 209 diusion 167, 242 diusion coecient 167 digestion under resistance heating 186 diode 66 diode AAS 149 diode array 70 diode-array 66 diode laser 154 diode laser atomic absorption spectrometry 176, see also diode laser AAS dipole 186 direct compact sample analysis 302 direct insertion probe 279 direct sample insertion 89, 228, 229 direct solids nebulizer 126 direct solids sampling 114, 117, 170, 174, 230, 268 discharge 2, 141 dielectric barrier (db) 281 electrodeless 235 hollow cathode 279, 295 restricted 136 dc 135 rf 135 single-electrode 235 spark 127 diuse spark 127 discharge gap 213 discharge lamp a ¯oating anode tube 141 ¯at cathode 141 discharge parameter 141 discharge under reduced pressure 11, 31, 135, 152, 297 discharges under reduced pressure 177, 294 discrete sampling 99, 161, 222 dispenser 165 dispersive element 52...
recombination process 110 reduced pressure discharge 2, see glow discharge reducing ¯ame 159 reduction 112 reference element 85, 125, 151 reference signal 197 re¯ectivity 196 re¯ectron 256 refractive index 154 refractory 110 refractory carbide 112 refractory element 164 refractory powder 229, 232, 304 refractory sample 186 relative method 197 relative method of analysis 170 relative sensitivity factor 281 relative standard deviation 195 remote sampling 125 removal 100 repeatability 36 repeller 76 residence time 109, 167, 258 residual gas impurity 276 resistance 214 resolution 78, 79, 277 resolving power 148 resonance ¯uorescence 292 resonance line 156, 163, 183 resonance radiation 148 resonant transition 298 resonator 132, 234, 236 response time 291 restrictor tube con®guration 142 Reticon 66 reversed-phase chromatography 271 rf coil 256 rf discharge 138 rf glow discharge 144 rf shielding 278 rf-GD-MS 283, 286 rf-powered glow discharge 278 rinsing time 222 R-L-C-circuit 221 rotating arc 118 rotation mill 302 rotation ± vibration band spectra 210 rotation ± vibration hyper®ne structure 178 rotational energy 24 rotational hyper®ne structure 23 RSF 284, 286 Russell and Saunders 7...
 Analytical Atomic Spectrometry with Flames and Plasmas. Jose A. C. Broekaert Copyright > 2002 Wiley-VCH Verlag GmbH & Co. KGaA ISBNs: 3-527-30146-1 (Hardback); 3-527-60062-0 (Electronic)...
T1 and T2 are the Bohr energy levels and the complexity of the emission spectra can be related to the complexity of the structure of the atomic energy levels. For an atom with a nucleus charge Z and one valence electron, the energy of this electron is given by : EÀ 2 Á p Á Z 2 Á e4 Á m n2h2 7...
1.1 Atomic structure
Fig. 1. Atomic energy level diagram for the sodium atom. (Reprinted with permission from Ref. [3].)...
as n Sm n m . The sum Zm Sm gm Á exp ÀEm akT is the partition function. This is a function of the temperature and the coecients of this function for a large number of neutral and ionized species are listed in the literature (see e.g. Ref. [5]). When Eq is expressed in eV, Eq. (20) can be written as: log naq log na log nq À 5040aT Á Vq À log Z 21...
Thus each process is in equilibrium with the inverse process and the Boltzmann distribution of each state is maintained by collisions of the ®rst and the second kind, including the ones with electrons, and there are no losses of energy through the emission of radiation or any absorption of radiation from an external source. In a real radiation source this perfect equilibrium cannot exist and there are losses of energy as a result of the emission and absorption of radiation, which also have to be considered. However, as long as both only slightly aect the energy balance, the system is in so-called local thermal equilibrium and: a Á N Á n0 ae Á ne Á n0 B H Á rn Á n0 b Á N Á nq b e Á ne Á nq A B Á rn Á nq from which nq an0 can be calculated as: nq an0 a Á N ae Á ne B H Á ru a b Á N b e Á ne A B Á ru 27 26...
For the case of stimulated emission, atoms in the excited state q only decay when they receive radiation of the wavelength lqp and ÀdNq dt Bqp Á Nq Á rn For the case of thermal equilibrium: gq Á Bqp gp Á Bpq 33 32...
For the case of a 2 kW inductively coupled plasma the four iron lines Fe I 381.58 nm, Fe I 383.04 nm, Fe I 382.44 nm and Fe I 382.58 nm have relative intensities of 5, 10, 2.3 and 7.4 a.u., respectively. When using the transition probability products gA of 66, 36, 1.26 and 26 (see Ref. [9]) as well as the excitations energies of 38175, 33096, 26140 and 33507 cmÀ1 , respectively, it can be calculated that the excitation temperature should be 5000 K. Limitations to the spectroscopic measurement of the temperatures from line intensities lie in possible deviations from ideal thermodynamic behavior in real radiation sources, but also in the poor accuracy of transition probabilities. They can be calculated from quantum mechanics, and have been determined and compiled by Corliss and Bozman at NIST [10] from measurements using a copper dc arc. These tables contain line energy levels, transition probabilities and the so-called oscillator strengths for ca. 25000 lines between 200 and 900 nm for 112 spectra of 70 elements. Between the oscillator strength f qp ( being 0.01 ± 0.1 for non-resonance and nearer to 1 for resonance lines) there is the relationship [11]: f qp gq agp  Aqp  m Á c 3 a 8 Á p 2 Á e 2 Á n 2 and f qp 1X499  10À16  l 2  gq agp  Aqp 43 42...
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