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preface to fifteenth edition

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SPECTROSCOPY 7.41<br />

The ionization constant can be calculated from the Saha equation:<br />

E 5 g g<br />

log Ki<br />

5040 log T 6.49 log<br />

T 2 g M<br />

i M e<br />

where E i is the ionization potential of the metal in eV (Table 4.2), T is the absolute temperature of<br />

the plasma (in kelvins), and the g terms are the statistical weights of the ionized a<strong>to</strong>m, the electron,<br />

and the neutral a<strong>to</strong>m. For the alkali metals the final term is zero; for the alkaline earth metals, it is<br />

0.6.<br />

To suppress the ionization of a metal, another easily ionized metal (denoted a deionizer or<br />

radiation buffer) is added <strong>to</strong> the sample. To ensure that ionization is suppressed for the test element,<br />

the product (K i ) M p M of the deionizer must exceed the similar product for the test element one hundred-fold<br />

(for 1 percent residual ionization of the test element).<br />

7.5 INFRARED SPECTROSCOPY<br />

TABLE 7.20<br />

Absorption Frequencies of Single Bonds <strong>to</strong> Hydrogen<br />

Abbreviations Used in the Table<br />

m, moderately strong var, of variable strength<br />

m–s, moderate <strong>to</strong> strong w, weak<br />

s, strong w–m, weak <strong>to</strong> moderately strong<br />

Group Band, cm 1 Remarks<br />

Saturated C9H<br />

H<br />

9C9H<br />

H<br />

2975–2950 (s)<br />

Two or three bands usually; asymmetrical<br />

2885–2865 (w)<br />

and symmetrical CH stretching, respectively.<br />

In presence of double bond adjacent<br />

<strong>to</strong> CH 3 group symmetrical band<br />

splits in<strong>to</strong> two.<br />

1450–1260 (m) Sensitive <strong>to</strong> adjacent negative substituents<br />

H<br />

9C9<br />

H<br />

acyclic<br />

ca 2930 (s)<br />

2870–2840 (w)<br />

1480–1440 (m)<br />

ca 720 (w)<br />

Frequency increased in strained systems.<br />

Symmetrical band splits in<strong>to</strong> two bands<br />

when double bond adjacent.<br />

Scissoring mode<br />

Rocking mode<br />

Alkane residues attached <strong>to</strong> carbon<br />

Cyclopropane ca 3050 (w)<br />

540–500<br />

470–460 (s)<br />

CH stretching<br />

Aliphatic cyclopropanes<br />

Cyclobutanes<br />

Cyclopentanes<br />

580–490 (s)<br />

595–490 (s)<br />

Alkyl derivatives: 550–530 cm 1<br />

Alkyl derivatives: 585–530 cm 1

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