CCL:G: ortho and para hydrogen

Dear Devendra,
As I understand it, basically, two factors are often considered for the nuclear spin isomers: the nuclear magnetic effect and the nuclear volume effect. The former can be detected and predicted by NMR j-coupling, and for the latter, Prof. Chris Cramer's group are doing calculations on it. Please check the supporting info. of this paper:
Wiederhold, J. G.; Cramer, C. J.; Daniel, K.; et al. Environ. Sci. Technol. 2010, 44, 4191-4197.
regards,
Hao-Bo Guo

On Tue, Dec 11, 2012 at 9:42 AM, Devendra Mani devdmani10|gmail.com <owner-chemistry*|*ccl.net> wrote:
Dear Prof. Mehdi , 
  I appreciate your generous reply. But the input format you have sent is for hydrogen (I=1/2) and deuterium (I=1) isotopes not for ortho and para-molecular hydrogen (o-H2 and p-H2). 
It will be very helpful if we could get the way for the nuclear spin isomers of molecular hydrogen.
Thanks and regards,
Devendra 


On Thu, Dec 6, 2012 at 11:38 PM, Mehdi Esrafili m_esrafili*|*yahoo.com <owner-chemistry:+:ccl.net> wrote:
Dear Devendra;
This is my second reply to your question. When I visited Gaussian help today, I saw an interesting way to difine nuclear parameters such as isotope, nuclear spin, ... within input file. In order to define these parameter, in the molecular specification section use :
atomic symbol (Iso=m,Spin=n) x  y  z    (where m is the isotope and n is nuclear spin in unit of 1/2).

this is an input for ortho hydrogen:

%chk=ortho.chk
# hf/3-21g
 
Title Card Required
 
0 2
H(Iso=1,Spin=2) 0.0 0.0 0.0

and for para:

%chk=ortho.chk
# hf/3-21g
 
Title Card Required
 
0 2
H(Iso=1,Spin=1) 0.0 0.0 0.0

I hope you find this information helpful.
Best regards
 
 
------------------------------------------------------------------------------------------------------------------------------  
`The man who makes no mistakes does not usually make anything.'
                                  Edward John Phelps (1822-1900)
------------------------------------------------------------------------------------------------------------------------------
Mehdi D. Esrafili, Ph.D.
Assistant Professor of Physical Chemistry 
Current address: Department of Chemistry,
Faculty of Basic Sciences,University of
Maragheh, Iran.
E-mail 1: m_esrafili[A]yahoo.com
E-mail 2: esrafili[A]maragheh.ac.ir
------------------------------------------------------------------------------------------------------------------------------

From: Mehdi Esrafili m_esrafili^_^yahoo.com <owner-chemistry[A]ccl.net>
To: "Esrafili, Mehdi D " <m_esrafili[A]yahoo.com>
Sent: Wednesday, December 5, 2012 9:49 PM
Subject: CCL:G: ortho and para hydrogen

Dear Devendr;
As we know, in Gaussian program we set electronic spin state rather than nuclear spin state. So, in my opinion, there is no way to define ortho/para hydrogen atom.
best regards
Mehdi
 
 
------------------------------------------------------------------------------------------------------------------------------  
`The man who makes no mistakes does not usually make anything.'
                                  Edward John Phelps (1822-1900)
------------------------------------------------------------------------------------------------------------------------------
Mehdi D. Esrafili, Ph.D.
Assistant Professor of Physical Chemistry 
Current address: Department of Chemistry,
Faculty of Basic Sciences,University of
Maragheh, Iran.
E-mail 1: m_esrafili*|*http://yahoo.com" target="_blank">yahoo.com
E-mail 2: esrafili*|*maragheh.ac.ir
------------------------------------------------------------------------------------------------------------------------------

From: Devendra Mani devdmani10%x%gmail.com <owner-chemistry*|*ccl.net>
To: "Esrafili, Mehdi D " <m_esrafili*|*yahoo.com>
Sent: Wednesday, December 5, 2012 8:39 PM
Subject: CCL:G: ortho and para hydrogen

Hi, 
 Is there any way to define ortho (spin I=1) and para (spin I=1/2) hydrogen spin isomers in gaussian?

Your suggestions will be highly appreciated. 


Regards,
Devendra Mani
IISc Bangalore, India