This could be the portrait of Elizaveta Aleksandrovna von Klinger. A genealogical sketch for Elizaveta Aleksandrovna von Klinger, daughter of Catherine the Great and Gregori Orlov has this portrait. She had a sister, Natalia Buxhoevdena.
This image was originally posted on 28 June 2011, but it had to be reposted so text could be added above the image to explain it might be the portrait of another person.
Empress Elizabeth wears a rectangular ruff and a spectacular diamond head band and waist band in this 1807 Mosnier portrait that was presumably a close up based on the 1805 portrait.
Keywords: 1807, Mosnier, Elizabeth Alexeievna, Princess, Tsaritsa, Baden family, Romanov family, Russian, curly coiffure, circlet, ribbon headdress, fitted bodice, U-décolletage, modesty piece, lce-trimmed neckline ruff, order star, order chain, quarter length tight sleeves, jeweled cuffs, jeweled waist band, Empire waistline, close skirt, robes