## What is a symmetry species?

There are a limited number of ways in which an arbitrary function can transform under the symmetry operations of a group, giving rise to a limited number of symmetry species. Any function that forms a basis for a matrix representation of a group must transform as one of the symmetry species of the group.

**What is symmetry adapted linear combination?**

SALCs (Symmetry Adapted Linear Combinations) are the linear combinations of basis sets composed of the stretching vectors of the molecule. The SALCs of a molecule can help determine binding schemes and symmetries. The procedure used to determine the SALCs of a molecule is also used to determine the LCAO of a molecule.

### What is an irreducible representation chemistry?

In a given representation (reducible or irreducible), the characters of all matrices belonging to symmetry operations in the same class are identical. The number of irreducible representations of a group is equal to the number of classes in the group.

**What is LCAO principle?**

L.C.A.O. principle is involved in the formation of molecular orbitals according to molecular obtital theory. The energy of bonding molecular orbital is less than that of the combining atomic orbitals while that of the anitibonding bonding melecular orbital is more.

#### What is A1g symmetry?

A1g is a non-degenerate total-symmetric vibration, that means it is symmetric under all symmetry operations (rotation, mirror plane, inversion center). E12g is a double-degenerate vibration that is symmetric under inversion (that’s the g).

**What is meant by irreducible representations?**

In mathematics, specifically in the representation theory of groups and algebras, an irreducible representation or irrep of an algebraic structure is a nonzero representation that has no proper nontrivial subrepresentation , with closed under the action of .

## Why is sigma bond stronger than pi bond?

Since the information of a sigma bond, the orbitals are along internuclear axis this results in more effective orbital overlap as compared to when pi bonds are formed as they are perpendicular to the internuclear axis. This significant difference in orbital overlap results in sigma bond being stronger than the pi bond.

**Which condition is not Favourable for the combination of atomic orbitals?**

Solution : The conditions for the combination of atomic orbitals are 1) The combining atomic orbitals should have comparable energy. 1s orbital can combine with another 1 s orbital but not with 2s orbital.

### What is T1g and T2G?

For T sets, T1g is assigned when both orbitals are in same plane like dxy, dx2-y2 and T2g is assigned when orbitals are orthogonal to each other like dxy, dz2!

**What is C2v symmetry?**

The C2v Point Group This point group contains four symmetry operations: E the identity operation. C2 a twofold symmetry axis. σv the first mirror plane (xz) σv’ the second mirror plane (yz)

#### What is reducible representation in group theory?

Definition. Reducible representation of a group G. A representation of a group G is said to be “reducible” if it is equivalent to a representation Γ of G that has the form of Equation (4.8) for all T ∈ G. It follows from Equations (4.1) and (4.8) that. for n = 1, 2,…,s1 and all T ∈ G.