Subject: Re: CCL:triplet and singlet gap of C2

From: John Kerkines <[email-masked]>
Date: Tue, 11 Apr 2000 15:47:16 +0300 (EET DST)

On Mon, 10 Apr 2000, Ohyun Kwon wrote:

> Dear CCLer's;
> Could anybody give some information about C2?
> C2 can have triplet or singlet state and I would like to know which is
> more stable and what is the energy gap between two states? 
> Thank you in advance.
> 
> yours
> 

Hi Ohyun,

Huber and Herzberg's "Constants of Diatomic Molecules" (1979) gives a
'singlet sigma g plus' ground state with a first excited 'triplet pi u'
state and an experimental gap of 716.2 cm**-1 (i.e. a gap of only ~2
kcal/mol).

I guess that the ground state should correlate to the M=+/-1 and -/+1
ground state carbons (triplet P), and the first excited to the M=0 and
M=+/-1 ground state carbons.

Regards,
John Kerkines
University of Athens, Greece