Pāṇini sūtras

The acute is optionally on the first syllable when the word adhyakṣa follows.

1. vibhāṣāविभाषा

   Part	Lexeme	Sandhi form	Meaning	Stem + termination
   vव्	vibhāṣविभाष्	vibhāṣāविभाषा	option	vibhāṣविभाष् + plus āआ

2. adhyakṣeअध्यक्षे

   Part	Lexeme	Sandhi form	Meaning	Stem + termination
   aअ	adhyakṣaअध्यक्ष	adhyakṣeअध्यक्षे	adhyakṣa [word]अध्यक्ष [wओर्द्]	adhyakṣअध्यक्ष् + plus eए

Anuvṛtti

1. pūrva+padamपूर्व+पदम् 6·2·1

   Part	Lexeme	Sandhi form	Meaning	Stem + termination
   pप्	pūrvaपूर्व	pūrvaपूर्व	antecedent	pūrvaपूर्व
   pप्	padaपद	padamपदम्	word	padपद् + plus amअम्

2. udāttaḥउदात्तः 6·2·64

   Part	Lexeme	Sandhi form	Meaning	Stem + termination
   uउ	udāttaउदात्त	udāttaḥउदात्तः	udāttaउदात्त	udāttउदात्त् + plus aḥअः