Hello Ajay Khanna

I know that to get MOs of a system using Gaussian you can use the keyword "pop=full" for getting all MOs and create chk file in Link commands line to use it after complete calculations to visualize the MOs. you can find the coefficients  in output file after the following line:

Molecular Orbital Coefficients

1 2

O V EIGENVALUES -- -0.41454 0.42759

1 1 H 1S 0.54884 1.21245

2 2 H 1S 0.54884 -1.21245

this output for hydrogen molecule using: #T b3lyp sto-3g pop=full

these coefficients  can use to get MOs of H2 that is a linear combination of Atomic orbitals of two hydrogen atoms:

Psi=C1*Phi1 + C1*Phi2  where here  C1=C2=0.54884.

I hope that helpful for you. Sorry if no new info^^

Regards

safiya Amer

Dear Safiya, thanks for your answer, I also know how to obtain there C1 & C2 but I'm not looking for these I'm looking for the exponents that are present in the phi1 & phi2 (phi1= e^(-a1/r^2), this a1 value). If you know this please do let me know.

Thanks,

Regards

Ajay Khanna

Mr. Khanna,

To the route section you should add: cube=orbital.

To the molecula specification section you should add:

.........

coordinates

........

XX, YY

name_orbital.cub

XX and YY are numbers of the orbitals.

Dear Bojidarka B. Ivanova, thank you for your answer but it still not giving me the values of exponent that I'm looking for. Can you please provide an example input for these coefficients and exponents are generated?

Regards

Ajay Khanna

You get that(value of a1 cofficiant) from the web site that you are mention. for example:

Phi1=0.156285*e^(-5.447178*r^2)+.904691*e^(-0.824547*r^2)+1.00000*e^(-0.183192*r^2).

this is for H2 molecule using 3-21G basis set. You can check that from the web site.

To write Phi2 it can use same cofficiants in phi1 but replace r^2 by (r-0.74)^2.

Regards.

Mr. Khanna,

As a "golden standard" in context of your question is CASSCF method. However the method does not provide a standard input, because of you should model the active space according to your molecule.

You can use CASSCF with surface hopping method, tolerating both computations in ground and excited states.

There is detail instruction in the Gaussian's IOP manual, here:

http://wild.life.nctu.edu.tw/~jsyu/compchem/g09/iops2.pdf

Gaussin incorporates the Tully and Preston surface hopping method, among others. More detail can be found, here:

Tully, J; Preston, R. M. J. Chem. Phys. 1971, 55, 562

More detail about CASSCF can be found, here:

Roos, B.; Lindh, R.; Malmqvist, P.; Veryazov, V.; Widmark, P. Multiconfigurational quantum chemistry, Wiley, 2016, Hoboken, pp. 1–224

The output-file contains the coefficients in a tabulated form.

For example:

BOTTOM WEIGHT= 9 TOP WEIGHT= 26

Configuration 1 Symmetry 1 11a000

Configuration 2 Symmetry 1 110a00

Configuration 3 Symmetry 1 1a1000

....................

EIGENVALUES AND EIGENVECTORS OF CI MATRIX

( 1) EIGENVALUE -388.0723003097

( 1) 0.7925011 ( 2) 0.3933095 ( 6) 0.2161863 ( 8) 0.1558111 ( 24) 0.1371253 ( 5)-0.1300020 ( 127) 0.1162492

( 15) 0.0937298 ( 14)-0.0825510 ( 68) 0.0774955 ( 13)-0.0662623 ( 162) 0.0642517 ( 16)-0.0608381 ( 4) 0.0603751

( 11)-0.0594692 ( 7)-0.0592648 ( 90) 0.0583697 ( 47) 0.0550625 ( 59) 0.0549462 ( 26) 0.0547194 ( 69) 0.0496602

( 103) 0.0489010 ( 200) 0.0468051 ( 61) 0.0452159 ( 91) 0.0427709 ( 93) 0.0417126 ( 17)-0.0394165 ( 50) 0.0385474

( 122) 0.0382095 ( 71) 0.0368204 ( 204) 0.0361288 ( 60) 0.0357384 ( 48) 0.0349283 ( 255) 0.0312502 ( 136) 0.0310117

( 31) 0.0301003 ( 64) 0.0275448 ( 10)-0.0268459 ( 3) 0.0267235 ( 123) 0.0265766 ( 98) 0.0254652 ( 18) 0.0246191

( 234) 0.0244259 ( 176) 0.0239411 ( 29)-0.0234819 ( 23) 0.0233236 ( 56) 0.0228605 ( 9)-0.0217129 ( 180) 0.0214087

( 161) 0.0207766 (

.................

************************************************

Surface hop control

************************************************

Leave Link 1003 at Sun Mar 04 12:42:13 2018, MaxMem= 34603008 cpu: 5.0

(Enter C:\g09w\l601.exe)

Copying SCF densities to generalized density rwf, IOpCl= 0 IROHF=3.

**********************************************************************

Population analysis using the SCF density.

**********************************************************************

Alpha occ. eigenvalues -- 0.00000 0.00000 0.00000 0.00000 0.00000

.............................................

Molecular Orbital Coefficients:

1 2 3 4 5

O O O O O

Eigenvalues -- 0.00000 0.00000 0.00000 0.00000 0.00000

1 1 N 1S -0.00003 -0.00001 0.99340 -0.00044 0.00000

2 2S 0.00036 0.00000 0.03112 0.00029 0.00030

3 2PX 0.00039 0.00003 0.00002 -0.00027 -0.00007

4 2PY -0.00023 0.00001 0.00030 -0.00016 0.00010

5 2PZ 0.00006 0.00000 0.00239 0.00001 0.00005

6 2 C 1S 0.00000 0.00001 0.00049 0.00000 -0.00144

7 2S 0.00001 0.00000 -0.00547 -0.00012 -0.00784

8 2PX 0.00004 -0.00002 -0.00327 0.00007 0.00444

9 2PY 0.00004 0.00006 0.00305 -0.00002 0.00174

10 2PZ -0.00001 0.00001 0.00069 0.00000 -0.00012

11 3 C 1S 0.00056 0.00001 0.00048 0.00052 0.00012

12 2S -0.00679 -0.00004 -0.00481 -0.00574 -0.00007

13 2PX -0.00504 0.00006 -0.00050 0.00465 0.00013

14 2PY 0.00344 -0.00005 -0.00414 0.00153 -0.00006

15 2PZ -0.00068 0.00000 0.00042 0.00018 -0.00003

16 4 O 1S 0.99431 0.00000 -0.00004 -0.00002 0.00000

17 2S 0.02557 -0.00002 0.00032 0.00013 -0.00004

18 2PX -0.00433 0.00001 0.00007 -0.00027 0.00002

19 2PY 0.00301 -0.00001 0.00038 -0.00026 -0.00001

20 2PZ -0.00060 0.00000 -0.00006 0.00002 0.00000

21 5 N 1S -0.00002 0.00006 0.00039 0.99366 -0.00002

22 2S 0.00018 0.00054 0.00030 0.02941 0.00026

23 2PX 0.00027 -0.00035 0.00003 0.00089 0.00007

.....................................................