anger vs heat of passion

anger

noun
  • A strong feeling of displeasure, hostility or antagonism towards someone or something, usually combined with an urge to harm, often stemming from perceived provocation, hurt, or threat. 

verb
  • To become angry. 

  • To cause such a feeling of antagonism in. 

heat of passion

noun
  • An outburst of anger that leads one to commit a criminal act, and is itself influenced by preceding events that might cause a reasonable person to lose self control. 

How often have the words anger and heat of passion occurred in a corpus of books? (source: Google Ngram Viewer )