Payal posted an Question
October 16, 2021 • 03:20 am 30 points
  • CSIR NET
  • Physical Sciences

Ex. find accoustical & optical branches in following solids ) diamond (ii) graphite (ii) graphene

Ex. Find accoustical & optical branches in following solids ) Diamond (ii) Graphite (ii) Graphene

1 Answer(s) Answer Now
  • 0 Likes
  • 4 Comments
  • 0 Shares
  • Payal

    And if so then why we take p=4 in graphite inspite of being having 2 atom basis

  • Payal

    If graphite and graphene both are two atom basis with 2 D structure ,then their no. of branches should be same

    eduncle-logo-app

    Graphite is a 2D structure having atomic basis 4 ... four carbon atoms are bonded in a basis whereas in graphene atoms basis is 2

    eduncle-logo-app

    Thanks

  • Payal

    but in diamond no. of atoms per unit permittive cell are 8 and in graphene these are 6 as u write that in graphite we have 4 atoms per unit permittive cell

    eduncle-logo-app

    Yes you are right no of primitive cells is 8 but here we check the no. of atoms in basis so Diamond is a 3D crystal structure with a face centered cubic Bravais lattice and "two atoms in the basis". We used this value as p and similar for graphite and graphene it is a 2D structure with no. of atomic basis 2.

whatsapp-btn

Do You Want Better RANK in Your Exam?

Start Your Preparations with Eduncle’s FREE Study Material

  • Updated Syllabus, Paper Pattern & Full Exam Details
  • Sample Theory of Most Important Topic
  • Model Test Paper with Detailed Solutions
  • Last 5 Years Question Papers & Answers