| Origin | 
          State Origin. | 
           
           | 
        
        
          | Width | 
          Linewidth (rotation independent) for state. | 
           
           | 
        
        
          | B | 
          Rotational constant. | 
          Rotation 
           | 
        
        
          | A | 
          Spin-orbit coupling constant. | 
          Spin-Orbit | 
        
        
          | LambdaSS | 
          Spin - spin coupling constant (=1.5*ε). | 
          Spin-Spin | 
        
        
          | o | 
          Spin-spin coupling constant giving lambda doubling for
            Omega = 0 states. | 
          Λ Doubling | 
        
        
          | theta | 
          Higher Order Spin-Spin interaction (S>=2 only). | 
          Spin-Spin | 
        
        
          | Gamma | 
          Spin rotation coupling constant. | 
          Spin-Rotation  | 
        
        
          | p | 
          Lambda doubling constant. | 
          Λ Doubling  | 
        
        
          | q | 
          Lambda doubling constant. | 
          Λ Doubling  | 
        
        
          | D | 
          Quartic centrifugal distortion. | 
          Rotation | 
        
        
          | H | 
          Sextic centrifugal distortion. | 
          Rotation | 
        
        
          | L | 
          J8
            centrifugal distortion. | 
          Rotation | 
        
        
          | M | 
          J10
            centrifugal distortion. | 
          Rotation | 
        
        
          | PP | 
          J12
            centrifugal distortion. (Not P to avoid confusion with p.) | 
          Rotation | 
        
        
          | AD | 
          Centrifugal distortion of A. | 
          Spin-Orbit | 
        
        
          | LambdaD | 
          Centrifugal Distortion of Lambda. | 
          Spin-Spin | 
        
        
          | LambdaH | 
          J4
            Centrifugal Distortion of Lambda. | 
          Spin-Spin | 
        
        
          | oD | 
          Centrifugal distortion of o. | 
          Λ Doubling  | 
        
        
          | oH | 
          J4
            Centrifugal distortion of o. | 
          Λ Doubling  | 
        
        
          | oL | 
          J6
            Centrifugal distortion of o. | 
          Λ Doubling  | 
        
        
          | pD | 
          Centrifugal distortion of p. | 
          Λ Doubling  | 
        
        
          | pH | 
          J6
            Centrifugal distortion of p. | 
          Λ Doubling  | 
        
        
          | pL | 
          J8
            Centrifugal distortion of p. | 
          Λ Doubling  | 
        
        
          | qD | 
          Centrifugal distortion of q. | 
          Λ Doubling  | 
        
        
          | qH | 
          J6
            Centrifugal distortion of q. | 
          Λ Doubling  | 
        
        
          | qL | 
          J8
            Centrifugal distortion of q. | 
          Λ Doubling  | 
        
        
          | gammaD | 
          Centrifugal distortion of gamma. | 
          Spin-Rotation  | 
        
        
          | gammaH | 
          J6
            Centrifugal distortion of gamma. | 
          Spin-Rotation  | 
        
        
          | gammaL | 
          J8
            Centrifugal distortion of gamma. | 
          Spin-Rotation  | 
        
        
          | eta | 
          Additional spin orbit term for quartet and
            higher states | 
          Spin-Orbit | 
        
        
          | gammaS | 
          Additional spin rotation term for quartet and
            higher states | 
          Spin-Orbit |