try this link

http://www.cup.uni-muenchen.de/ch/compchem/geom/scan.html

http://joaquinbarroso.com/2010/04/19/pesscan/

Thank u so much Mohammad Alam.

I am sorry Mohammad Alam, If possible please send a sample .gjf file of any molecule with more number of atoms.

Hi Vikas,

on the following site you can find example and if you don't want to visit this, I've pasted a gjf file below...

http://www.cup.uni-muenchen.de/ch/compchem/geom/scan.html

# opt=z-matrix hf/3-21g nosymm

Title Card Required

0 1

C

H 1 B1

H 1 B2 2 A1

H 1 B3 2 A2 3 D1 0

C 1 B4 4 A3 2 D2 0

H 5 B5 1 A4 4 D3 0

H 5 B6 1 A5 4 D4 0

H 5 B7 1 A6 4 D5 0

B1 1.07000000

B2 1.07000000

B3 1.07000000

B4 1.54000000

B5 1.07000000

B6 1.07000000

B7 1.07000000

A1 109.47125080

A2 109.47121829

A3 109.47123134

A4 109.47120255

A5 109.47120255

A6 109.47123134

D1 -120.00001416

D2 119.99998297

D4 180.00000000

D5 -60.00004130

D3=59.99995130 s 30 +5.0

I hope it'll help....but you can visit the site given by Mr. Alam and Me.

Best of Luck

Mehboob

Thank you so much Mehboob and Alam, now I am able to scan dihedral angle. thank u so much

Well I'm both Mehboob and Alam :-)