1. INTRODUCTION  
   
2. OBSERVATIONS AND REDUCTION  
2.1. Spitzer-IRS  
2.2. Keck-NIRSPEC  

3. CORRELATIONS  

4. LTE MODELS  
4.1. Description of modeling procedures  

5. SUMMARY OF RESULTS  

6. DISCUSSION  
6.1. Completeness of the observed chemistry  
6.2. The column density of the molecular layer  
6.3. Implications for the carbon deficit in the inner solar system  
6.4. Abundant acetylene and aromatic hydrocarbons  
6.5. Conclusion