Distinguishing two mechanisms for enhanced ionization of <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:msub><mml:mi mathvariant="normal">H</mml:mi><mml:mn>2</mml:mn></mml:msub><mml:msup><mml:mrow /><mml:mo>+</mml:mo></mml:msup></mml:mrow></mml:math> using orthogonal two-color laser fields

We theoretically study the ionization enhancement of diatomic molecular ion ${\mathrm{H}}_{2}{}^{+}$ at two critical internuclear distances $R$, using orthogonal two-color laser fields. The polarization fundamental infrared field and a weak second-harmonic is parallel perpendicular to axis, respectively. It observed that adding raises slightly first peak smaller whereas it enhances second one larger $R$ significantly. further analyze observable evidence which distinguishes underlying mechanisms responsible for enhanced ${\mathrm{H}}_{2}{}^{+}$: (i) resonant excitation along with coherent interference ionizing wave packets from $1s{\ensuremath{\sigma}}_{g}$ $2p{\ensuremath{\sigma}}_{u}$ states (ii) easier up-field site molecule.