Answers Section Ans

The simplified theory allows the time-dependent wave function to be calculated rapidly for any specified laser field. However, controlling the dynamics of the charge carriers requires the answer to an inverse question [18-22]. That is, given a specific target or objective, what is the laser field that best drives the system to that objective Several methods have been developed to address this question. This section sketches one method, valid in the weak response (perturbative) regime in which most experiments on semiconductors are performed. 

As noted in the last section, the correct answer to an analysis is usually not known in advance. So the key question becomes How can a laboratory be absolutely sure that the result it is reporting is accurate First, the bias, if any, of a method must be determined and the method must be validated as mentioned in the last section (see also Section 5.6). Besides periodically checking to be sure that all instruments and measuring devices are calibrated and functioning properly, and besides assuring that the sample on which the work was performed truly represents the entire bulk system (in other words, besides making certain the work performed is free of avoidable error), the analyst relies on the precision of a series of measurements or analysis results to be the indicator of accuracy. If a series of tests all provide the same or nearly the same result, and that result is free of bias or compensated for bias, it is taken to be an accurate answer. Obviously, what degree of precision is required and how to deal with the data in order to have the confidence that is needed or wanted are important questions. The answer lies in the use of statistics. Statistical methods take a look at the series of measurements that are the data, provide some mathematical indication of the precision, and reject or retain outliers, or suspect data values, based on predetermined limits. 

Within each section of a chapter, this icon announces, Here ends theory and Let the practice begin. Alongside the icon is an example problem that employs the very concept covered in that section. An answer and explanation accompany each practice problem. 

No claim can be made that a complete review has been made of the reactions which qualify for discussion in this section. An attempt was made, however, to present enough of the observations so that the different aspects of behavior which seem significant are outlined. Much interesting work readily suggests itself it is much more difficult, however, to devise experiments for these labile systems which will lead to definite answers to the important question how are the various groups known to be in the activated complex arranged with respect to each other ... 

Note Many constructed-response questions on chemistry certification exams consist of quantitative problem solving with the requirement to show your work. Questions 102 and 104 are of this type. For additional practice, I recommend solving quantitative problems from the multiple-choice sample questions with an constructed-response mindset and comparing your answers to the solutions shown in the Sample Constructed-Response Answers section. Some constructed-response questions require little or no quantitative problem solving, but they ask for an experimental design or analysis of a design. Questions 101 and 103 are of this type. These questions usually have no single correct solution. 

Glossary and Answers The book ends with a glossary of important terms and concepts (including the section number where the term was first introduced), an answer section, and a detailed index. 

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