Quantum Mechanics II & Atomic Physics (IFS (Forests Services) Physics (Mains)): Questions 1 - 2 of 2

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Question number: 1

» Quantum Mechanics II & Atomic Physics » Atomic Physics » Spectroscopic Notation of Atomic States

Appeared in Year: 2011

Essay Question▾

Describe in Detail

Obtain the term symbols for two singlet states and two triplet states for two electron atoms. (Paper-2) (Section-A)


If we knowing the value of various types of angular momenta, term symbols gives three kinds of information,

Total orbital angular momentum, L

Multiplicity of the terms,

Total angular momentum,

Vectors sum of angular momentum

Vectors Sum of Angular Momentum

In figure vectors sum of angular momentum is shown.

  • We can do vector sums of these vector. But it be

… (160 more words) …

Question number: 2

» Quantum Mechanics II & Atomic Physics » Quantum Mechanics II » The Spin Half Problem and Properties of Pauli Spin Matrices

Appeared in Year: 2011

Essay Question▾

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What are Pauli spin matrices?

Show that:

Where, are Pauli spin matrices and and are vector operators which commute with , but do not necessarily commute with each other?


Pauli spin matrices or Pauli matrices are a set of matrices, which are complex, Hermitian and unitary matrices. Pauli spin matrices defined as,

The Pauli vector is defined by,

From question another vector operators are and are given.

Now, mapping mechanism from a Pauli matrix

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